Solved

restrict keychars on textbox

Posted on 2013-01-07
8
565 Views
Last Modified: 2013-01-07
Hi EE,

I need to restrict keyPress on a textBox. I only want the following :

Any digits before the dot, then after the dot only one of those:   25, 50 75

so for examples this is good:

4
34
12.25
9.50
66.75


this is wrong:

2.4
11.57
34.52
3.02

can you help ?
0
Comment
Question by:PhilippeRenaud
  • 4
  • 3
8 Comments
 
LVL 42

Expert Comment

by:sedgwick
ID: 38751183
here:

Private Sub textBox1_KeyDown(sender As Object, e As KeyEventArgs)
	e.Handled = EvaluateText(e.KeyChar)
End Sub

Private Function EvaluateText(key As String) As Boolean
        If key = "." And textBox1.Text.Contains(".") Then
            Return False
        End If

        Dim data As String = textBox1.Text + key
       Dim d As Decimal = Decimal.Parse(data)
        Dim dec As Decimal = d - Math.Floor(d)
        Dim arr As Decimal() = {0.25D, 0.5D, 0.75D, 0}

        If arr.Contains(dec) Then
            Return True
        End If
        Return False

    End Function

Open in new window

0
 
LVL 1

Author Comment

by:PhilippeRenaud
ID: 38751218
what is d ?
0
 
LVL 1

Author Comment

by:PhilippeRenaud
ID: 38751222
nevermind ..
0
 
LVL 42

Accepted Solution

by:
sedgwick earned 500 total points
ID: 38751231
i;ve made a mistake in the function, here's working:

Private Sub textBox1_KeyDown(sender As Object, e As KeyEventArgs)
	e.Handled = EvaluateText(e.KeyChar)
End Sub

Private Function EvaluateText(key As String) As Boolean
  If key = "." And textBox1.Text.Contains(".") Then
            Return True
        End If

        If Not key = "." And Not TextBox1.Text.Contains(".") Then
            Return False
        End If

        Dim data As String = textBox1.Text + key
        Dim d As Decimal = Decimal.Parse(data)
        Dim dec As Decimal = d - Math.Floor(d)
        Dim arr As Decimal() = {0.25D, 0.5D, 0.75D, 0}

        If arr.Contains(dec) Then
            Return False
        End If
        Return True

    End Function

Open in new window

0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 
LVL 1

Author Comment

by:PhilippeRenaud
ID: 38751241
if I add Cchar(Backspace) i would put it where?
0
 
LVL 42

Expert Comment

by:sedgwick
ID: 38751252
it would be easier for you to have numeric control and combobox control with {.25,.50,.75,0} values.
screenshot
cause the validation code is overkill to what you want to achieve.
using 2 controls and your validation is complete, no errors.
0
 
LVL 1

Author Closing Comment

by:PhilippeRenaud
ID: 38751261
thanks, let me think about that combox Box yes.
thanks
0
 
LVL 74

Expert Comment

by:käµfm³d 👽
ID: 38751453
I'd suggest deriving from the existing TextBox so that you have a resusable component.

e.g.

Public Class QuarterlyTextbox
    Inherits TextBox

    Private _validKeys As New List(Of Keys) From
    {
            Keys.D0, Keys.NumPad0,
            Keys.D1, Keys.NumPad1,
            Keys.D2, Keys.NumPad2,
            Keys.D3, Keys.NumPad3,
            Keys.D4, Keys.NumPad4,
            Keys.D5, Keys.NumPad5,
            Keys.D6, Keys.NumPad6,
            Keys.D7, Keys.NumPad7,
            Keys.D8, Keys.NumPad8,
            Keys.D9, Keys.NumPad9,
            Keys.Decimal, Keys.OemPeriod
    }

    Private _controlKeys As New List(Of Keys) From
    {
            Keys.Back, Keys.Delete,
            Keys.Left, Keys.Right,
            Keys.Home, Keys.End
    }

    Protected Overrides Sub OnKeyDown(e As KeyEventArgs)
        If _controlKeys.Contains(e.KeyData) Then
            MyBase.OnKeyDown(e)
            Return
        End If

        If (Not _validKeys.Contains(e.KeyData)) OrElse
           (Me.Text.EndsWith(".25") OrElse Me.Text.EndsWith(".50") OrElse Me.Text.EndsWith(".75")) OrElse
           (Me.Text.Contains(".") AndAlso (e.KeyData = Keys.Decimal OrElse e.KeyData = Keys.OemPeriod)) OrElse
           (Me.Text.EndsWith(".") AndAlso e.KeyData <> Keys.D2 AndAlso e.KeyData <> Keys.NumPad2 _
                                  AndAlso e.KeyData <> Keys.D5 AndAlso e.KeyData <> Keys.NumPad5 _
                                  AndAlso e.KeyData <> Keys.D7 AndAlso e.KeyData <> Keys.NumPad7) OrElse
           ((Me.Text.EndsWith(".2") OrElse Me.Text.EndsWith(".7")) AndAlso e.KeyData <> Keys.D5 AndAlso e.KeyData <> Keys.NumPad5) OrElse
           (Me.Text.EndsWith(".5") AndAlso e.KeyData <> Keys.D0 AndAlso e.KeyData <> Keys.NumPad0) Then
            e.SuppressKeyPress = True
            e.Handled = True
            Return
        End If

        MyBase.OnKeyDown(e)
    End Sub

End Class

Open in new window


If you added this code to your project, then built it, you would then have a component you can drag from the ToolBox onto your form.

Screenshot
0

Featured Post

Highfive Gives IT Their Time Back

Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

Join & Write a Comment

Suggested Solutions

In my previous article (http://www.experts-exchange.com/Programming/Languages/.NET/.NET_Framework_3.x/A_4362-Serialization-in-NET-1.html) we saw the basics of serialization and how types/objects can be serialized to Binary format. In this blog we wi…
Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
Learn how to match and substitute tagged data using PHP regular expressions. Demonstrated on Windows 7, but also applies to other operating systems. Demonstrated technique applies to PHP (all versions) and Firefox, but very similar techniques will w…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

708 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now