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How to detect if data has changed on a VB.net 2010 windows form
Coming from a long background in VB6 I can get creative with detecting 'isDirty' with key down, mouse down and such. With what I've found on the web, that process from VB6 seems like it is either overly complicated (or under complicated) comparatively for vb.net.
My form contains a mixture of (all bound to Access tables) masked text, textbox, Combobox and DateTime picker.
I've searched far and wide and am astounded by the diversity of ideas to process these events; which is why I'm back here.
Questions:
1. What are best (accepted) practices to handle this?
2. Code sample?
My form contains a mixture of (all bound to Access tables) masked text, textbox, Combobox and DateTime picker.
I've searched far and wide and am astounded by the diversity of ideas to process these events; which is why I'm back here.
Questions:
1. What are best (accepted) practices to handle this?
2. Code sample?
Who is Participating?
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LVL 72
is your form bound to a business object (a class exposing the properties)? In this case, it would be easy to set a IsDirty flag in all the setters!
still if you are having a business object, you can also have it automatically implemented by using PostSharp: http://doc.postsharp.net/inotifypropertychanged
I would do the below.
1> First define what is meant by dirty, would say a text box which contained ABC, was modified to AB or DE at some point and at later again made as ABC. User did some modification in this text box which might have resulted in some coupled changes in other fields, but later this text box was brought back to original value on load. Do you call this as dirty? Ideally I would not. But it is better to be clear.
2> For each control based on the definition in step 1, I would find out a way whether it is dirty from each control.
3> If there are controls in UI which contains a list of value (like combo or list box or list view) and it is bound to a collection of objects, it would be good to implement as Observable Collection, which gives events when Property is changed (INotifyPropertyChanged) or a collection is changed (INotifyCollectionChanged)
With this I can find out whether list has been modified (whether it is combo or list box).
4> So whenever a UI control it is bound to a property of class, I can figure it has changed using INotifyPropertyChanged Interface (INotifyPropertyChanged)
5> If I have a data table, I can call GetChanges method on Data Table to see if there are any uncommitted changes, if so GetChanges shall return a non null data table.
I shall see if I can provide you some example when I pick this up tomorrow.
Thanks,
Karrtik
1> First define what is meant by dirty, would say a text box which contained ABC, was modified to AB or DE at some point and at later again made as ABC. User did some modification in this text box which might have resulted in some coupled changes in other fields, but later this text box was brought back to original value on load. Do you call this as dirty? Ideally I would not. But it is better to be clear.
2> For each control based on the definition in step 1, I would find out a way whether it is dirty from each control.
3> If there are controls in UI which contains a list of value (like combo or list box or list view) and it is bound to a collection of objects, it would be good to implement as Observable Collection, which gives events when Property is changed (INotifyPropertyChanged) or a collection is changed (INotifyCollectionChanged)
With this I can find out whether list has been modified (whether it is combo or list box).
4> So whenever a UI control it is bound to a property of class, I can figure it has changed using INotifyPropertyChanged Interface (INotifyPropertyChanged)
5> If I have a data table, I can call GetChanges method on Data Table to see if there are any uncommitted changes, if so GetChanges shall return a non null data table.
I shall see if I can provide you some example when I pick this up tomorrow.
Thanks,
Karrtik
2 ways that I use, depending on the needs.
-----
There is a way to associate all the controls of a specific type to a single event method.
A variable at the Form level, let's call it IsDirty.
Create a KeyDown event procedure that is associated with no control. You simply create a KeyDown event and remove the Handles at the end of the declaration:
AddHandler DateTimePicker1.KeyDown, AddressOf Common_KeyDown
Adapt to your needs
-----
When I need to be more precise and prevent stuff such as making the thing IsDirty when the user makes a change but then undo it, I go as follow.
Once the form is filled with the original data, I run code like the following, to copy the original value in the Tag property of the controls. Once again, this need to be adjusted to your needs in situations, for instance, where not all the TextBoxes are considered to be candidates in the mechanism.
-----
There is a way to associate all the controls of a specific type to a single event method.
A variable at the Form level, let's call it IsDirty.
Create a KeyDown event procedure that is associated with no control. You simply create a KeyDown event and remove the Handles at the end of the declaration:
Private Sub Common_KeyDown(sender As Object, e As KeyEventArgs)
IsDirty = True
End Sub
For Each ctl As Control In Me.Controls
If TypeOf ctl Is TextBox OrElse TypeOf ctl Is ComboBox Then
AddHandler ctl.KeyDown, AddressOf Common_KeyDown
End If
Next
AddHandler DateTimePicker1.KeyDown, AddressOf Common_KeyDown
Adapt to your needs
-----
When I need to be more precise and prevent stuff such as making the thing IsDirty when the user makes a change but then undo it, I go as follow.
Once the form is filled with the original data, I run code like the following, to copy the original value in the Tag property of the controls. Once again, this need to be adjusted to your needs in situations, for instance, where not all the TextBoxes are considered to be candidates in the mechanism.
For Each ctl As Control In Me.Controls
If TypeOf ctl Is TextBox OrElse TypeOf ctl Is ComboBox Then
ctl.Tag = ctl.Text
End If
Next
DateTimePicker1.Tag = DateTimePicker1.Value
For Each ctl As Control In Me.Controls
If TypeOf ctl Is TextBox OrElse TypeOf ctl Is ComboBox Then
If ctl.Text <> CStr(ctl.Tag) then
IsDirty=True
Exit For
End If
End If
Next
If DateTimePicker1.Value <> CDate(DateTimePicker1.Tag) then IsDirty = True
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Along the same lines of what James has laid out, you could then use a pair of helper classes to make the implementation more generic and thereby more reusable.
Using http://www.codeproject.com/Articles/38756/Two-Simple-Approaches-to-WinForms-Dirty-Tracking as a basis:
DirtyFormTracker.vb -
Form1.vb -
From here you can do many different things depending upon how far you want to go. For example, you can make it so that the save button is only enabled when there are dirty controls (requires hooking into an event on the controls). You could even create a custom event on the dirty form tracker that alerts the form when it has dirty controls. Perhaps something like:
CleanlinessChangedEventHan
This is all reposted from a previous EE PAQ: http:/Q_28692186.html
I would definitely recommend reading through the posts there as well. Ark discusses using the RowState for databound items in order to determine dirtiness.
-saige-
Using http://www.codeproject.com/Articles/38756/Two-Simple-Approaches-to-WinForms-Dirty-Tracking as a basis:
DirtyFormTracker.vb -
Public Class DirtyFormTracker
Private fTrackedForm As Form
Private fTrackedControls As List(Of DirtyControlTracker)
Public ReadOnly Property IsDirty() As Boolean
Get
Return GetListOfDirtyControls().Count > 0
End Get
End Property
Public Sub New(ByVal parent As Form)
fTrackedForm = parent
fTrackedControls = New List(Of DirtyControlTracker)
AddControlsFromForm(parent)
End Sub
' utility method to add the controls from a Form to this collection
Public Sub AddControlsFromForm(ByVal frm As Form)
AddControlsFromCollection(frm.Controls)
End Sub
' recursive routine to inspect each control and add to the collection accordingly
Public Sub AddControlsFromCollection(ByVal coll As Control.ControlCollection)
For Each c As Control In coll
' if the control is supported for dirty tracking, add it
Try
If DirtyControlTracker.IsControlTypeSupported(c) Then
fTrackedControls.Add(New DirtyControlTracker(c))
End If
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
' recurively apply to inner collections
If c.HasChildren Then
AddControlsFromCollection(c.Controls)
End If
Next
End Sub
' loop through all controls and return a list of those that are dirty
Public Function GetListOfDirtyControls() As IEnumerable(Of DirtyControlTracker)
Return (From [control] As DirtyControlTracker In fTrackedControls Where [control].IsDirty() Select [control])
End Function
Public Sub MarkControlAsClean(ByVal tracker As DirtyControlTracker)
tracker.EstablishValueAsClean()
End Sub
' mark all the tracked controls as clean
Public Sub MarkAllControlsAsClean()
For Each c As DirtyControlTracker In fTrackedControls
c.EstablishValueAsClean()
Next
End Sub
End Class
Imports System.Text
Public Class DirtyControlTracker
Private fControl As Control
Private fCleanValue As String
' read only properties
Public ReadOnly Property [Control]() As Control
Get
Return fControl
End Get
End Property
Public ReadOnly Property CleanValue() As String
Get
Return fCleanValue
End Get
End Property
' constructor establishes the control and uses its current value as "clean"
Public Sub New(ByVal ctl As Control)
' if the control type is not one that is supported, throw an exception
If DirtyControlTracker.IsControlTypeSupported(ctl) Then
fControl = ctl
Else
Throw New NotSupportedException(String.Format("The control type for '{0}' is not supported by the ControlDirtyTracker class.", ctl.Name))
End If
End Sub
' method to establish the the current control value as "clean"
Public Sub EstablishValueAsClean()
fCleanValue = GetCurrentValue()
End Sub
' determine if the current control value is considered "dirty";
' i.e. if the current control value is different than the one
' remembered as "clean"
Public Function IsDirty() As Boolean
' compare the remembered "clean value" to the current value;
' if they are the same, the control is still clean;
' if they are different, the control is considered dirty.
Return (String.Compare(fCleanValue, GetCurrentValue(), False) <> 0)
End Function
' static class utility method; return whether or not the control type
' of the given control is supported by this class;
' developers may modify this to extend support for other types
Public Shared Function IsControlTypeSupported(ByVal ctl As Control) As Boolean
' list of types supported
If TypeOf ctl Is TextBox Then
Return True
End If
If TypeOf ctl Is CheckBox Then
Return True
End If
If TypeOf ctl Is ComboBox Then
Return True
End If
If TypeOf ctl Is ListBox Then
Return True
End If
If TypeOf ctl Is DateTimePicker Then
Return True
End If
If TypeOf ctl Is RadioButton Then
Return True
End If
' ... add additional types as desired ...
' not a supported type
Return False
End Function
' private method to determine the current value (as a string) of the control;
' if the control is not supported, return a NotSupported exception
' developers may modify this to extend support for other types
Public Function GetCurrentValue() As String
If TypeOf fControl Is TextBox Then
Return TryCast(fControl, TextBox).Text
End If
If TypeOf fControl Is CheckBox Then
Return TryCast(fControl, CheckBox).Checked.ToString()
End If
If TypeOf fControl Is ComboBox Then
Return TryCast(fControl, ComboBox).Text
End If
If TypeOf fControl Is ListBox Then
' for a listbox, create a list of the selected indexes
Dim val As New StringBuilder()
Dim lb As ListBox = TryCast(fControl, ListBox)
Dim coll As ListBox.SelectedIndexCollection = lb.SelectedIndices
For i As Integer = 0 To coll.Count - 1
val.AppendFormat("{0};", coll(i))
Next
Return val.ToString()
End If
If TypeOf fControl Is DateTimePicker Then
Return TryCast(fControl, DateTimePicker).Text
End If
If TypeOf fControl Is RadioButton Then
Return TryCast(fControl, RadioButton).Checked.ToString()
End If
Return ""
End Function
End Class
Form1.vb -
Imports System.Text
Public Class Form1
Private tracker As DirtyFormTracker
Private Sub OnLoad(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
tbFirstName.Text = "Paul"
tbLastName.Text = "Wilson"
dtpBirthday.Text = "01/01/2015"
cmbGender.Text = "Male"
cbAdministrator.Checked = True
rbGreen.Checked = True
tracker = New DirtyFormTracker(Me)
tracker.MarkAllControlsAsClean()
End Sub
Private Sub OnClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click, btnListDirtyControls.Click, btnClose.Click
If TypeOf sender Is Button Then
Dim btn As Button = DirectCast(sender, Button)
If btn.Equals(btnClose) Then
If tracker IsNot Nothing Then
If tracker.IsDirty() Then
If MessageBox.Show("Would you like to save changes before closing?", "Changes detected", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question) = DialogResult.Yes Then
For Each ctl In tracker.GetListOfDirtyControls()
tracker.MarkControlAsClean(ctl)
Next
Else
MessageBox.Show("The form is clean, so the window closes without prompting to save", "No changed detected", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
End If
End If
ElseIf btn.Equals(btnListDirtyControls) Then
If tracker IsNot Nothing Then
Dim builder As New StringBuilder()
For Each ctl In tracker.GetListOfDirtyControls()
builder.AppendLine(String.Format("{0}; Clean Value = {1}; Current Value = {2}", ctl.Control.Name, ctl.CleanValue, ctl.GetCurrentValue()))
Next
If builder.Length > 0 Then
builder.Insert(0, String.Format("The following controls are dirty:{0}", Environment.NewLine))
Else
builder.AppendLine("None of the controls are currently 'dirty'")
End If
MessageBox.Show(builder.ToString(), "Dirty Controls")
End If
ElseIf btn.Equals(btnSave) Then
If tracker IsNot Nothing Then
For Each ctl In tracker.GetListOfDirtyControls()
tracker.MarkControlAsClean(ctl)
Next
btn.Enabled = False
End If
End If
End If
End Sub
End Class
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Form1
Inherits System.Windows.Forms.Form
'Form overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
Try
If disposing AndAlso components IsNot Nothing Then
components.Dispose()
End If
Finally
MyBase.Dispose(disposing)
End Try
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> _
Private Sub InitializeComponent()
Me.Label1 = New System.Windows.Forms.Label()
Me.tbFirstName = New System.Windows.Forms.TextBox()
Me.tbLastName = New System.Windows.Forms.TextBox()
Me.Label2 = New System.Windows.Forms.Label()
Me.Label3 = New System.Windows.Forms.Label()
Me.dtpBirthday = New System.Windows.Forms.DateTimePicker()
Me.cmbGender = New System.Windows.Forms.ComboBox()
Me.Label4 = New System.Windows.Forms.Label()
Me.cbAdministrator = New System.Windows.Forms.CheckBox()
Me.GroupBox1 = New System.Windows.Forms.GroupBox()
Me.rbWhite = New System.Windows.Forms.RadioButton()
Me.rbBlack = New System.Windows.Forms.RadioButton()
Me.rbYellow = New System.Windows.Forms.RadioButton()
Me.rbBlue = New System.Windows.Forms.RadioButton()
Me.rbGreen = New System.Windows.Forms.RadioButton()
Me.rbRed = New System.Windows.Forms.RadioButton()
Me.btnSave = New System.Windows.Forms.Button()
Me.btnClose = New System.Windows.Forms.Button()
Me.btnListDirtyControls = New System.Windows.Forms.Button()
Me.GroupBox1.SuspendLayout()
Me.SuspendLayout()
'
'Label1
'
Me.Label1.AutoSize = True
Me.Label1.Location = New System.Drawing.Point(12, 8)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(60, 13)
Me.Label1.TabIndex = 0
Me.Label1.Text = "First Name:"
'
'tbFirstName
'
Me.tbFirstName.Location = New System.Drawing.Point(78, 5)
Me.tbFirstName.Name = "tbFirstName"
Me.tbFirstName.Size = New System.Drawing.Size(194, 20)
Me.tbFirstName.TabIndex = 1
'
'tbLastName
'
Me.tbLastName.Location = New System.Drawing.Point(78, 31)
Me.tbLastName.Name = "tbLastName"
Me.tbLastName.Size = New System.Drawing.Size(194, 20)
Me.tbLastName.TabIndex = 3
'
'Label2
'
Me.Label2.AutoSize = True
Me.Label2.Location = New System.Drawing.Point(11, 34)
Me.Label2.Name = "Label2"
Me.Label2.Size = New System.Drawing.Size(61, 13)
Me.Label2.TabIndex = 2
Me.Label2.Text = "Last Name:"
'
'Label3
'
Me.Label3.AutoSize = True
Me.Label3.Location = New System.Drawing.Point(24, 61)
Me.Label3.Name = "Label3"
Me.Label3.Size = New System.Drawing.Size(48, 13)
Me.Label3.TabIndex = 4
Me.Label3.Text = "Birthday:"
'
'dtpBirthday
'
Me.dtpBirthday.Location = New System.Drawing.Point(78, 57)
Me.dtpBirthday.Name = "dtpBirthday"
Me.dtpBirthday.Size = New System.Drawing.Size(194, 20)
Me.dtpBirthday.TabIndex = 5
'
'cmbGender
'
Me.cmbGender.FormattingEnabled = True
Me.cmbGender.Items.AddRange(New Object() {"Unknown", "Male", "Female", "Undeclared"})
Me.cmbGender.Location = New System.Drawing.Point(78, 84)
Me.cmbGender.Name = "cmbGender"
Me.cmbGender.Size = New System.Drawing.Size(194, 21)
Me.cmbGender.TabIndex = 6
'
'Label4
'
Me.Label4.AutoSize = True
Me.Label4.Location = New System.Drawing.Point(27, 87)
Me.Label4.Name = "Label4"
Me.Label4.Size = New System.Drawing.Size(45, 13)
Me.Label4.TabIndex = 7
Me.Label4.Text = "Gender:"
'
'cbAdministrator
'
Me.cbAdministrator.AutoSize = True
Me.cbAdministrator.Location = New System.Drawing.Point(175, 111)
Me.cbAdministrator.Name = "cbAdministrator"
Me.cbAdministrator.Size = New System.Drawing.Size(97, 17)
Me.cbAdministrator.TabIndex = 8
Me.cbAdministrator.Text = "Is Administrator"
Me.cbAdministrator.UseVisualStyleBackColor = True
'
'GroupBox1
'
Me.GroupBox1.Controls.Add(Me.rbWhite)
Me.GroupBox1.Controls.Add(Me.rbBlack)
Me.GroupBox1.Controls.Add(Me.rbYellow)
Me.GroupBox1.Controls.Add(Me.rbBlue)
Me.GroupBox1.Controls.Add(Me.rbGreen)
Me.GroupBox1.Controls.Add(Me.rbRed)
Me.GroupBox1.Location = New System.Drawing.Point(72, 134)
Me.GroupBox1.Name = "GroupBox1"
Me.GroupBox1.Size = New System.Drawing.Size(200, 85)
Me.GroupBox1.TabIndex = 9
Me.GroupBox1.TabStop = False
Me.GroupBox1.Text = "Favorite Color"
'
'rbWhite
'
Me.rbWhite.AutoSize = True
Me.rbWhite.Location = New System.Drawing.Point(103, 65)
Me.rbWhite.Name = "rbWhite"
Me.rbWhite.Size = New System.Drawing.Size(53, 17)
Me.rbWhite.TabIndex = 5
Me.rbWhite.TabStop = True
Me.rbWhite.Text = "White"
Me.rbWhite.UseVisualStyleBackColor = True
'
'rbBlack
'
Me.rbBlack.AutoSize = True
Me.rbBlack.Location = New System.Drawing.Point(103, 42)
Me.rbBlack.Name = "rbBlack"
Me.rbBlack.Size = New System.Drawing.Size(52, 17)
Me.rbBlack.TabIndex = 4
Me.rbBlack.TabStop = True
Me.rbBlack.Text = "Black"
Me.rbBlack.UseVisualStyleBackColor = True
'
'rbYellow
'
Me.rbYellow.AutoSize = True
Me.rbYellow.Location = New System.Drawing.Point(104, 19)
Me.rbYellow.Name = "rbYellow"
Me.rbYellow.Size = New System.Drawing.Size(56, 17)
Me.rbYellow.TabIndex = 3
Me.rbYellow.TabStop = True
Me.rbYellow.Text = "Yellow"
Me.rbYellow.UseVisualStyleBackColor = True
'
'rbBlue
'
Me.rbBlue.AutoSize = True
Me.rbBlue.Location = New System.Drawing.Point(7, 66)
Me.rbBlue.Name = "rbBlue"
Me.rbBlue.Size = New System.Drawing.Size(46, 17)
Me.rbBlue.TabIndex = 2
Me.rbBlue.TabStop = True
Me.rbBlue.Text = "Blue"
Me.rbBlue.UseVisualStyleBackColor = True
'
'rbGreen
'
Me.rbGreen.AutoSize = True
Me.rbGreen.Location = New System.Drawing.Point(7, 43)
Me.rbGreen.Name = "rbGreen"
Me.rbGreen.Size = New System.Drawing.Size(54, 17)
Me.rbGreen.TabIndex = 1
Me.rbGreen.TabStop = True
Me.rbGreen.Text = "Green"
Me.rbGreen.UseVisualStyleBackColor = True
'
'rbRed
'
Me.rbRed.AutoSize = True
Me.rbRed.Location = New System.Drawing.Point(7, 20)
Me.rbRed.Name = "rbRed"
Me.rbRed.Size = New System.Drawing.Size(45, 17)
Me.rbRed.TabIndex = 0
Me.rbRed.TabStop = True
Me.rbRed.Text = "Red"
Me.rbRed.UseVisualStyleBackColor = True
'
'btnSave
'
Me.btnSave.Location = New System.Drawing.Point(116, 227)
Me.btnSave.Name = "btnSave"
Me.btnSave.Size = New System.Drawing.Size(75, 23)
Me.btnSave.TabIndex = 10
Me.btnSave.Text = "Save"
Me.btnSave.UseVisualStyleBackColor = True
'
'btnClose
'
Me.btnClose.Location = New System.Drawing.Point(197, 227)
Me.btnClose.Name = "btnClose"
Me.btnClose.Size = New System.Drawing.Size(75, 23)
Me.btnClose.TabIndex = 11
Me.btnClose.Text = "Close"
Me.btnClose.UseVisualStyleBackColor = True
'
'btnListDirtyControls
'
Me.btnListDirtyControls.Location = New System.Drawing.Point(12, 227)
Me.btnListDirtyControls.Name = "btnListDirtyControls"
Me.btnListDirtyControls.Size = New System.Drawing.Size(98, 23)
Me.btnListDirtyControls.TabIndex = 12
Me.btnListDirtyControls.Text = "List Dirty Controls"
Me.btnListDirtyControls.UseVisualStyleBackColor = True
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(284, 262)
Me.Controls.Add(Me.btnListDirtyControls)
Me.Controls.Add(Me.btnClose)
Me.Controls.Add(Me.btnSave)
Me.Controls.Add(Me.GroupBox1)
Me.Controls.Add(Me.cbAdministrator)
Me.Controls.Add(Me.Label4)
Me.Controls.Add(Me.cmbGender)
Me.Controls.Add(Me.dtpBirthday)
Me.Controls.Add(Me.Label3)
Me.Controls.Add(Me.tbLastName)
Me.Controls.Add(Me.Label2)
Me.Controls.Add(Me.tbFirstName)
Me.Controls.Add(Me.Label1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.GroupBox1.ResumeLayout(False)
Me.GroupBox1.PerformLayout()
Me.ResumeLayout(False)
Me.PerformLayout()
End Sub
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents tbFirstName As System.Windows.Forms.TextBox
Friend WithEvents tbLastName As System.Windows.Forms.TextBox
Friend WithEvents Label2 As System.Windows.Forms.Label
Friend WithEvents Label3 As System.Windows.Forms.Label
Friend WithEvents dtpBirthday As System.Windows.Forms.DateTimePicker
Friend WithEvents cmbGender As System.Windows.Forms.ComboBox
Friend WithEvents Label4 As System.Windows.Forms.Label
Friend WithEvents cbAdministrator As System.Windows.Forms.CheckBox
Friend WithEvents GroupBox1 As System.Windows.Forms.GroupBox
Friend WithEvents rbWhite As System.Windows.Forms.RadioButton
Friend WithEvents rbBlack As System.Windows.Forms.RadioButton
Friend WithEvents rbYellow As System.Windows.Forms.RadioButton
Friend WithEvents rbBlue As System.Windows.Forms.RadioButton
Friend WithEvents rbGreen As System.Windows.Forms.RadioButton
Friend WithEvents rbRed As System.Windows.Forms.RadioButton
Friend WithEvents btnSave As System.Windows.Forms.Button
Friend WithEvents btnClose As System.Windows.Forms.Button
Friend WithEvents btnListDirtyControls As System.Windows.Forms.Button
End Class
CleanlinessChangedEventHan
Public Delegate Sub CleanlinessChangedEventHandler(ByVal sender As Object, ByVal e As EventArgs)
Public Class DirtyFormTracker
Private ReadOnly fCleanlinessChanged As New List(Of CleanlinessChangedEventHandler)
Public Custom Event CleanlinessChanged As CleanlinessChangedEventHandler
AddHandler(ByVal value As CleanlinessChangedEventHandler)
fCleanlinessChanged.Add(value)
End AddHandler
RemoveHandler(ByVal value As CleanlinessChangedEventHandler)
fCleanlinessChanged.Remove(value)
End RemoveHandler
RaiseEvent(ByVal sender As Object, ByVal e As EventArgs)
For Each handler As CleanlinessChangedEventHandler In fCleanlinessChanged
Try
handler.Invoke(sender, e)
Catch ex As Exception
Debug.WriteLine(String.Format("Exception while invoking event handler: {0}", ex))
End Try
Next
End RaiseEvent
End Event
Private fTrackedForm As Form
Private fTrackedControls As List(Of DirtyControlTracker)
Public ReadOnly Property IsDirty() As Boolean
Get
Return GetListOfDirtyControls().Count > 0
End Get
End Property
Public Sub New(ByVal parent As Form)
fTrackedForm = parent
fTrackedControls = New List(Of DirtyControlTracker)
AddControlsFromForm(parent)
End Sub
' utility method to add the controls from a Form to this collection
Public Sub AddControlsFromForm(ByVal frm As Form)
AddControlsFromCollection(frm.Controls)
End Sub
' recursive routine to inspect each control and add to the collection accordingly
Public Sub AddControlsFromCollection(ByVal coll As Control.ControlCollection)
For Each c As Control In coll
' if the control is supported for dirty tracking, add it
Try
If DirtyControlTracker.IsControlTypeSupported(c) Then
Dim controlTracker As New DirtyControlTracker(c)
AddHandler controlTracker.CleanlinessChanged, AddressOf OnCleanLinessChanged
fTrackedControls.Add(controlTracker)
End If
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
' recurively apply to inner collections
If c.HasChildren Then
AddControlsFromCollection(c.Controls)
End If
Next
End Sub
' loop through all controls and return a list of those that are dirty
Public Function GetListOfDirtyControls() As IEnumerable(Of DirtyControlTracker)
Return (From [control] As DirtyControlTracker In fTrackedControls Where [control].IsDirty() Select [control])
End Function
Public Sub MarkControlAsClean(ByVal tracker As DirtyControlTracker)
tracker.EstablishValueAsClean()
End Sub
' mark all the tracked controls as clean
Public Sub MarkAllControlsAsClean()
For Each c As DirtyControlTracker In fTrackedControls
c.EstablishValueAsClean()
Next
End Sub
Private Sub OnCleanLinessChanged(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent CleanlinessChanged(Me, e)
End Sub
End Class
Imports System.Text
Public Class DirtyControlTracker
Private ReadOnly fCleanlinessChanged As New List(Of CleanlinessChangedEventHandler)
Public Custom Event CleanlinessChanged As CleanlinessChangedEventHandler
AddHandler(ByVal value As CleanlinessChangedEventHandler)
fCleanlinessChanged.Add(value)
End AddHandler
RemoveHandler(ByVal value As CleanlinessChangedEventHandler)
fCleanlinessChanged.Remove(value)
End RemoveHandler
RaiseEvent(ByVal sender As Object, ByVal e As EventArgs)
For Each handler As CleanlinessChangedEventHandler In fCleanlinessChanged
Try
handler.Invoke(sender, e)
Catch ex As Exception
Debug.WriteLine(String.Format("Exception while invoking event handler: {0}", ex))
End Try
Next
End RaiseEvent
End Event
Private fControl As Control
Private fCleanValue As String
' read only properties
Public ReadOnly Property [Control]() As Control
Get
Return fControl
End Get
End Property
Public ReadOnly Property CleanValue() As String
Get
Return fCleanValue
End Get
End Property
' constructor establishes the control and uses its current value as "clean"
Public Sub New(ByVal ctl As Control)
' if the control type is not one that is supported, throw an exception
If DirtyControlTracker.IsControlTypeSupported(ctl) Then
fControl = ctl
AssignHandlerForDataChanged(ctl)
Else
Throw New NotSupportedException(String.Format("The control type for '{0}' is not supported by the ControlDirtyTracker class.", ctl.Name))
End If
End Sub
' method to establish the the current control value as "clean"
Public Sub EstablishValueAsClean()
fCleanValue = GetCurrentValue()
End Sub
' determine if the current control value is considered "dirty";
' i.e. if the current control value is different than the one
' remembered as "clean"
Public Function IsDirty() As Boolean
' compare the remembered "clean value" to the current value;
' if they are the same, the control is still clean;
' if they are different, the control is considered dirty.
Return (String.Compare(fCleanValue, GetCurrentValue(), False) <> 0)
End Function
' static class utility method; return whether or not the control type
' of the given control is supported by this class;
' developers may modify this to extend support for other types
Public Shared Function IsControlTypeSupported(ByVal ctl As Control) As Boolean
' list of types supported
If TypeOf ctl Is TextBox Then
Return True
ElseIf TypeOf ctl Is CheckBox Then
Return True
ElseIf TypeOf ctl Is ComboBox Then
Return True
ElseIf TypeOf ctl Is ListBox Then
Return True
ElseIf TypeOf ctl Is DateTimePicker Then
Return True
ElseIf TypeOf ctl Is RadioButton Then
Return True
End If
' ... add additional types as desired ...
' not a supported type
Return False
End Function
' private method to determine the current value (as a string) of the control;
' if the control is not supported, return a NotSupported exception
' developers may modify this to extend support for other types
Public Function GetCurrentValue() As String
If TypeOf fControl Is TextBox Then
Return TryCast(fControl, TextBox).Text
ElseIf TypeOf fControl Is CheckBox Then
Return TryCast(fControl, CheckBox).Checked.ToString()
ElseIf TypeOf fControl Is ComboBox Then
Return TryCast(fControl, ComboBox).Text
ElseIf TypeOf fControl Is ListBox Then
' for a listbox, create a list of the selected indexes
Dim val As New StringBuilder()
Dim lb As ListBox = TryCast(fControl, ListBox)
Dim coll As ListBox.SelectedIndexCollection = lb.SelectedIndices
For i As Integer = 0 To coll.Count - 1
val.AppendFormat("{0};", coll(i))
Next
Return val.ToString()
ElseIf TypeOf fControl Is DateTimePicker Then
Return TryCast(fControl, DateTimePicker).Text
ElseIf TypeOf fControl Is RadioButton Then
Return TryCast(fControl, RadioButton).Checked.ToString()
End If
Return ""
End Function
Private Sub AssignHandlerForDataChanged(ByVal ctl As Control)
If TypeOf ctl Is TextBox Then
AddHandler ctl.TextChanged, AddressOf OnChanged
ElseIf TypeOf ctl Is CheckBox Then
AddHandler DirectCast(ctl, CheckBox).CheckedChanged, AddressOf OnChanged
ElseIf TypeOf ctl Is ComboBox Then
AddHandler DirectCast(ctl, ComboBox).SelectedValueChanged, AddressOf OnChanged
ElseIf TypeOf ctl Is ListBox Then
AddHandler DirectCast(ctl, ListBox).SelectedValueChanged, AddressOf OnChanged
ElseIf TypeOf ctl Is DateTimePicker Then
AddHandler DirectCast(ctl, DateTimePicker).ValueChanged, AddressOf OnChanged
ElseIf TypeOf ctl Is RadioButton Then
AddHandler DirectCast(ctl, RadioButton).CheckedChanged, AddressOf OnChanged
End If
End Sub
Private Sub OnChanged(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent CleanlinessChanged(Me, e)
End Sub
End Class
Imports System.Text
Public Class Form1
Private WithEvents tracker As DirtyFormTracker
Private Sub OnLoad(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
tbFirstName.Text = "Paul"
tbLastName.Text = "Wilson"
dtpBirthday.Text = "01/01/2015"
cmbGender.Text = "Male"
cbAdministrator.Checked = True
rbGreen.Checked = True
tracker = New DirtyFormTracker(Me)
tracker.MarkAllControlsAsClean()
btnSave.Enabled = tracker.IsDirty()
End Sub
Private Sub OnCleanlinessChanged(ByVal sender As Object, ByVal e As EventArgs) Handles tracker.CleanlinessChanged
If TypeOf sender Is DirtyFormTracker Then
Dim formTracker As DirtyFormTracker = DirectCast(sender, DirtyFormTracker)
btnSave.Enabled = formTracker.IsDirty()
End If
End Sub
Private Sub OnClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click, btnListDirtyControls.Click, btnClose.Click
If TypeOf sender Is Button Then
Dim btn As Button = DirectCast(sender, Button)
If btn.Equals(btnClose) Then
If tracker IsNot Nothing Then
If tracker.IsDirty() Then
If MessageBox.Show("Would you like to save changes before closing?", "Changes detected", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question) = DialogResult.Yes Then
For Each ctl In tracker.GetListOfDirtyControls()
tracker.MarkControlAsClean(ctl)
Next
Else
MessageBox.Show("The form is clean, so the window closes without prompting to save", "No changed detected", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
End If
End If
ElseIf btn.Equals(btnListDirtyControls) Then
If tracker IsNot Nothing Then
Dim builder As New StringBuilder()
For Each ctl In tracker.GetListOfDirtyControls()
builder.AppendLine(String.Format("{0}; Clean Value = {1}; Current Value = {2}", ctl.Control.Name, ctl.CleanValue, ctl.GetCurrentValue()))
Next
If builder.Length > 0 Then
builder.Insert(0, String.Format("The following controls are dirty:{0}", Environment.NewLine))
Else
builder.AppendLine("None of the controls are currently 'dirty'")
End If
MessageBox.Show(builder.ToString(), "Dirty Controls")
End If
ElseIf btn.Equals(btnSave) Then
If tracker IsNot Nothing Then
For Each ctl In tracker.GetListOfDirtyControls()
tracker.MarkControlAsClean(ctl)
Next
btn.Enabled = False
End If
End If
End If
End Sub
End Class
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Form1
Inherits System.Windows.Forms.Form
'Form overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
Try
If disposing AndAlso components IsNot Nothing Then
components.Dispose()
End If
Finally
MyBase.Dispose(disposing)
End Try
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> _
Private Sub InitializeComponent()
Me.Label1 = New System.Windows.Forms.Label()
Me.tbFirstName = New System.Windows.Forms.TextBox()
Me.tbLastName = New System.Windows.Forms.TextBox()
Me.Label2 = New System.Windows.Forms.Label()
Me.Label3 = New System.Windows.Forms.Label()
Me.dtpBirthday = New System.Windows.Forms.DateTimePicker()
Me.cmbGender = New System.Windows.Forms.ComboBox()
Me.Label4 = New System.Windows.Forms.Label()
Me.cbAdministrator = New System.Windows.Forms.CheckBox()
Me.GroupBox1 = New System.Windows.Forms.GroupBox()
Me.rbWhite = New System.Windows.Forms.RadioButton()
Me.rbBlack = New System.Windows.Forms.RadioButton()
Me.rbYellow = New System.Windows.Forms.RadioButton()
Me.rbBlue = New System.Windows.Forms.RadioButton()
Me.rbGreen = New System.Windows.Forms.RadioButton()
Me.rbRed = New System.Windows.Forms.RadioButton()
Me.btnSave = New System.Windows.Forms.Button()
Me.btnClose = New System.Windows.Forms.Button()
Me.btnListDirtyControls = New System.Windows.Forms.Button()
Me.GroupBox1.SuspendLayout()
Me.SuspendLayout()
'
'Label1
'
Me.Label1.AutoSize = True
Me.Label1.Location = New System.Drawing.Point(12, 8)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(60, 13)
Me.Label1.TabIndex = 0
Me.Label1.Text = "First Name:"
'
'tbFirstName
'
Me.tbFirstName.Location = New System.Drawing.Point(78, 5)
Me.tbFirstName.Name = "tbFirstName"
Me.tbFirstName.Size = New System.Drawing.Size(194, 20)
Me.tbFirstName.TabIndex = 1
'
'tbLastName
'
Me.tbLastName.Location = New System.Drawing.Point(78, 31)
Me.tbLastName.Name = "tbLastName"
Me.tbLastName.Size = New System.Drawing.Size(194, 20)
Me.tbLastName.TabIndex = 3
'
'Label2
'
Me.Label2.AutoSize = True
Me.Label2.Location = New System.Drawing.Point(11, 34)
Me.Label2.Name = "Label2"
Me.Label2.Size = New System.Drawing.Size(61, 13)
Me.Label2.TabIndex = 2
Me.Label2.Text = "Last Name:"
'
'Label3
'
Me.Label3.AutoSize = True
Me.Label3.Location = New System.Drawing.Point(24, 61)
Me.Label3.Name = "Label3"
Me.Label3.Size = New System.Drawing.Size(48, 13)
Me.Label3.TabIndex = 4
Me.Label3.Text = "Birthday:"
'
'dtpBirthday
'
Me.dtpBirthday.Location = New System.Drawing.Point(78, 57)
Me.dtpBirthday.Name = "dtpBirthday"
Me.dtpBirthday.Size = New System.Drawing.Size(194, 20)
Me.dtpBirthday.TabIndex = 5
'
'cmbGender
'
Me.cmbGender.FormattingEnabled = True
Me.cmbGender.Items.AddRange(New Object() {"Unknown", "Male", "Female", "Undeclared"})
Me.cmbGender.Location = New System.Drawing.Point(78, 84)
Me.cmbGender.Name = "cmbGender"
Me.cmbGender.Size = New System.Drawing.Size(194, 21)
Me.cmbGender.TabIndex = 6
'
'Label4
'
Me.Label4.AutoSize = True
Me.Label4.Location = New System.Drawing.Point(27, 87)
Me.Label4.Name = "Label4"
Me.Label4.Size = New System.Drawing.Size(45, 13)
Me.Label4.TabIndex = 7
Me.Label4.Text = "Gender:"
'
'cbAdministrator
'
Me.cbAdministrator.AutoSize = True
Me.cbAdministrator.Location = New System.Drawing.Point(175, 111)
Me.cbAdministrator.Name = "cbAdministrator"
Me.cbAdministrator.Size = New System.Drawing.Size(97, 17)
Me.cbAdministrator.TabIndex = 8
Me.cbAdministrator.Text = "Is Administrator"
Me.cbAdministrator.UseVisualStyleBackColor = True
'
'GroupBox1
'
Me.GroupBox1.Controls.Add(Me.rbWhite)
Me.GroupBox1.Controls.Add(Me.rbBlack)
Me.GroupBox1.Controls.Add(Me.rbYellow)
Me.GroupBox1.Controls.Add(Me.rbBlue)
Me.GroupBox1.Controls.Add(Me.rbGreen)
Me.GroupBox1.Controls.Add(Me.rbRed)
Me.GroupBox1.Location = New System.Drawing.Point(72, 134)
Me.GroupBox1.Name = "GroupBox1"
Me.GroupBox1.Size = New System.Drawing.Size(200, 85)
Me.GroupBox1.TabIndex = 9
Me.GroupBox1.TabStop = False
Me.GroupBox1.Text = "Favorite Color"
'
'rbWhite
'
Me.rbWhite.AutoSize = True
Me.rbWhite.Location = New System.Drawing.Point(103, 65)
Me.rbWhite.Name = "rbWhite"
Me.rbWhite.Size = New System.Drawing.Size(53, 17)
Me.rbWhite.TabIndex = 5
Me.rbWhite.TabStop = True
Me.rbWhite.Text = "White"
Me.rbWhite.UseVisualStyleBackColor = True
'
'rbBlack
'
Me.rbBlack.AutoSize = True
Me.rbBlack.Location = New System.Drawing.Point(103, 42)
Me.rbBlack.Name = "rbBlack"
Me.rbBlack.Size = New System.Drawing.Size(52, 17)
Me.rbBlack.TabIndex = 4
Me.rbBlack.TabStop = True
Me.rbBlack.Text = "Black"
Me.rbBlack.UseVisualStyleBackColor = True
'
'rbYellow
'
Me.rbYellow.AutoSize = True
Me.rbYellow.Location = New System.Drawing.Point(104, 19)
Me.rbYellow.Name = "rbYellow"
Me.rbYellow.Size = New System.Drawing.Size(56, 17)
Me.rbYellow.TabIndex = 3
Me.rbYellow.TabStop = True
Me.rbYellow.Text = "Yellow"
Me.rbYellow.UseVisualStyleBackColor = True
'
'rbBlue
'
Me.rbBlue.AutoSize = True
Me.rbBlue.Location = New System.Drawing.Point(7, 66)
Me.rbBlue.Name = "rbBlue"
Me.rbBlue.Size = New System.Drawing.Size(46, 17)
Me.rbBlue.TabIndex = 2
Me.rbBlue.TabStop = True
Me.rbBlue.Text = "Blue"
Me.rbBlue.UseVisualStyleBackColor = True
'
'rbGreen
'
Me.rbGreen.AutoSize = True
Me.rbGreen.Location = New System.Drawing.Point(7, 43)
Me.rbGreen.Name = "rbGreen"
Me.rbGreen.Size = New System.Drawing.Size(54, 17)
Me.rbGreen.TabIndex = 1
Me.rbGreen.TabStop = True
Me.rbGreen.Text = "Green"
Me.rbGreen.UseVisualStyleBackColor = True
'
'rbRed
'
Me.rbRed.AutoSize = True
Me.rbRed.Location = New System.Drawing.Point(7, 20)
Me.rbRed.Name = "rbRed"
Me.rbRed.Size = New System.Drawing.Size(45, 17)
Me.rbRed.TabIndex = 0
Me.rbRed.TabStop = True
Me.rbRed.Text = "Red"
Me.rbRed.UseVisualStyleBackColor = True
'
'btnSave
'
Me.btnSave.Location = New System.Drawing.Point(116, 227)
Me.btnSave.Name = "btnSave"
Me.btnSave.Size = New System.Drawing.Size(75, 23)
Me.btnSave.TabIndex = 10
Me.btnSave.Text = "Save"
Me.btnSave.UseVisualStyleBackColor = True
'
'btnClose
'
Me.btnClose.Location = New System.Drawing.Point(197, 227)
Me.btnClose.Name = "btnClose"
Me.btnClose.Size = New System.Drawing.Size(75, 23)
Me.btnClose.TabIndex = 11
Me.btnClose.Text = "Close"
Me.btnClose.UseVisualStyleBackColor = True
'
'btnListDirtyControls
'
Me.btnListDirtyControls.Location = New System.Drawing.Point(12, 227)
Me.btnListDirtyControls.Name = "btnListDirtyControls"
Me.btnListDirtyControls.Size = New System.Drawing.Size(98, 23)
Me.btnListDirtyControls.TabIndex = 12
Me.btnListDirtyControls.Text = "List Dirty Controls"
Me.btnListDirtyControls.UseVisualStyleBackColor = True
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(284, 262)
Me.Controls.Add(Me.btnListDirtyControls)
Me.Controls.Add(Me.btnClose)
Me.Controls.Add(Me.btnSave)
Me.Controls.Add(Me.GroupBox1)
Me.Controls.Add(Me.cbAdministrator)
Me.Controls.Add(Me.Label4)
Me.Controls.Add(Me.cmbGender)
Me.Controls.Add(Me.dtpBirthday)
Me.Controls.Add(Me.Label3)
Me.Controls.Add(Me.tbLastName)
Me.Controls.Add(Me.Label2)
Me.Controls.Add(Me.tbFirstName)
Me.Controls.Add(Me.Label1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.GroupBox1.ResumeLayout(False)
Me.GroupBox1.PerformLayout()
Me.ResumeLayout(False)
Me.PerformLayout()
End Sub
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents tbFirstName As System.Windows.Forms.TextBox
Friend WithEvents tbLastName As System.Windows.Forms.TextBox
Friend WithEvents Label2 As System.Windows.Forms.Label
Friend WithEvents Label3 As System.Windows.Forms.Label
Friend WithEvents dtpBirthday As System.Windows.Forms.DateTimePicker
Friend WithEvents cmbGender As System.Windows.Forms.ComboBox
Friend WithEvents Label4 As System.Windows.Forms.Label
Friend WithEvents cbAdministrator As System.Windows.Forms.CheckBox
Friend WithEvents GroupBox1 As System.Windows.Forms.GroupBox
Friend WithEvents rbWhite As System.Windows.Forms.RadioButton
Friend WithEvents rbBlack As System.Windows.Forms.RadioButton
Friend WithEvents rbYellow As System.Windows.Forms.RadioButton
Friend WithEvents rbBlue As System.Windows.Forms.RadioButton
Friend WithEvents rbGreen As System.Windows.Forms.RadioButton
Friend WithEvents rbRed As System.Windows.Forms.RadioButton
Friend WithEvents btnSave As System.Windows.Forms.Button
Friend WithEvents btnClose As System.Windows.Forms.Button
Friend WithEvents btnListDirtyControls As System.Windows.Forms.Button
End Class
I would definitely recommend reading through the posts there as well. Ark discusses using the RowState for databound items in order to determine dirtiness.
-saige-
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