Use a Dataset to store Property Information
Experts,
I am working with a DataGridView control builder. This Builder allows a user to select a DataSource and customize the DataGridView. All of the settings would be saved to an XML file which can be called by one Function and re-displayed. I can quickly use this builder to create a library of DataGridViews in any of my applications and not have to wory about individually coding each DataGridView. This will make for MUCH faster application developement and display of data for my customers.
I store the data for the DataGridView in a DataSet. This makes it easy to poass all of the necessary settings. Creating the structure of the dataset is not my problem, nor is creating XML files. The issue I am having now is storing the information for the Public Properties in a DataTable and calling them back later.
Say I have a Table called "Properties". This table has three columns; 1) PropertyName, 2) PropertyVariable, and 3) PropertyValue.
1. PropertyName is the abbreviated name of the Public Property Setting. 2) PropertyVariable is the FULL Public Propery Variable. 3) ProperyValue is the actual value for the Public Property. I know I can use Reflection to iterate Public Properties, but to store, Set and Get the value is my major issue right now.
Using PropertyInfo (pInfo) I can loop through the Public Properties and get the Name of the Public Property. I store this name in column 2 (PropertyName). How do I Get the value of the Public Property to store in (PropertyValue)? And also do the reverse which is to Set the value once read from column 3? At this point I am using a loop (iLoop) and want to take the PropertyName, match it to the Public Propery and Set the value. Could you show me a sample of code for this?
I am working with a DataGridView control builder. This Builder allows a user to select a DataSource and customize the DataGridView. All of the settings would be saved to an XML file which can be called by one Function and re-displayed. I can quickly use this builder to create a library of DataGridViews in any of my applications and not have to wory about individually coding each DataGridView. This will make for MUCH faster application developement and display of data for my customers.
I store the data for the DataGridView in a DataSet. This makes it easy to poass all of the necessary settings. Creating the structure of the dataset is not my problem, nor is creating XML files. The issue I am having now is storing the information for the Public Properties in a DataTable and calling them back later.
Say I have a Table called "Properties". This table has three columns; 1) PropertyName, 2) PropertyVariable, and 3) PropertyValue.
1. PropertyName is the abbreviated name of the Public Property Setting. 2) PropertyVariable is the FULL Public Propery Variable. 3) ProperyValue is the actual value for the Public Property. I know I can use Reflection to iterate Public Properties, but to store, Set and Get the value is my major issue right now.
Using PropertyInfo (pInfo) I can loop through the Public Properties and get the Name of the Public Property. I store this name in column 2 (PropertyName). How do I Get the value of the Public Property to store in (PropertyValue)? And also do the reverse which is to Set the value once read from column 3? At this point I am using a loop (iLoop) and want to take the PropertyName, match it to the Public Propery and Set the value. Could you show me a sample of code for this?
You can use GetValue an SetValue to get / set Values from Properties and also on members:
Const RefBF As BindingFlags = BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.Instance
dim PageInfo As FieldInfo = GetType(PrintPreviewContro
Dim x As PropertyInfo = GetType(PrintPreviewContro
Properties:
x.SetValue(Dlg.PrintPrevie
Debug.Print(x.GetValue(Dlg
Members:
PageInfo.SetValue(Dlg.Prin
Const RefBF As BindingFlags = BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.Instance
dim PageInfo As FieldInfo = GetType(PrintPreviewContro
Dim x As PropertyInfo = GetType(PrintPreviewContro
Properties:
x.SetValue(Dlg.PrintPrevie
Debug.Print(x.GetValue(Dlg
Members:
PageInfo.SetValue(Dlg.Prin
ASKER
I know the Property name because I have that defined in a table. I also know the type of the object wheather it is ingeter, etc. Here is an example:
I have a Form called DataSourceLink. On DataSourceLink I have Public Properties defined from class clsProp_DataSourceLinkProp
Given the above I want to store the value of the Property in column 3 of my table in the dataset I will write to an XML file. So I want to iterate throuth the properties of the class to get the value of the property for DataSetName using GetValue froim the PropertyInfo. What would the code in VB look like for this example. I would also like to see an example of SetValue using the same information provided. Each time I try to write the code I get an error.
I hope this clears things up a bit more. The class I am writing can be used on several different forms to help save and subsiquently recall data from the XML file.
I have a Form called DataSourceLink. On DataSourceLink I have Public Properties defined from class clsProp_DataSourceLinkProp
Given the above I want to store the value of the Property in column 3 of my table in the dataset I will write to an XML file. So I want to iterate throuth the properties of the class to get the value of the property for DataSetName using GetValue froim the PropertyInfo. What would the code in VB look like for this example. I would also like to see an example of SetValue using the same information provided. Each time I try to write the code I get an error.
I hope this clears things up a bit more. The class I am writing can be used on several different forms to help save and subsiquently recall data from the XML file.
Sub Save(FormType as Type, Frm As Form, MyTable as DataTable)
Dim properties = FormType.GetProperties 'Only Public Properties
For Each prop As PropertyInfo In properties
Dim Row = MyDataTable.rows.NewRow
Row("Form") = Frm.Name
Row("Property") = prop.Name
Row("Value") =prop.GetValue(Frm, Nothing)
rows.add(row)
Next
end sub
'Asume Primary Key - Form,Property
Sub Restore(FormType as Type, Frm As Form, MyTable as DataTable)
Dim properties = FormType.GetProperties 'Only Public Properties
Dim Key(1) as object
Key(0) = Frm.Name
For Each prop As PropertyInfo In properties
Key(1)= prop.Name
dim Row = MyTable.Rows.Find(key)
if Row isnot nothing then prop.SetValue(Frm, Row("Value"), Nothing)
Next
end sub
ASKER
x77,
I get an error on the first line 'Dim properties as FormType.GetProperties.
While FormType is Type it doesn't seam to map to GetType. I believe I understand the subroutine, but could you exlain this. Do I need to add any other imports besides System.Reflection?
I get an error on the first line 'Dim properties as FormType.GetProperties.
While FormType is Type it doesn't seam to map to GetType. I believe I understand the subroutine, but could you exlain this. Do I need to add any other imports besides System.Reflection?
Asume you Create a Form2 Class and create an instance from Form2:
Dim f as new Form2, Ty = Gettype(Form2) ' Ty = f.Gettype() - you can get Type from Object and also from class.
Restor3(Ty, f, MyTable)
F.ShowDialog
Save(Ty, f, MyTable)
Note that You need modify Save Method to allow Update:
Sub Save(FormType as Type, Frm As Form, MyTable as DataTable)
Dim properties = FormType.GetProperties 'Only Public Properties
Dim Key(1) as object
Key(0) = Frm.Name
For Each prop As PropertyInfo In properties
Key(1)= prop.Name
dim Row = MyTable.Rows.Find(key)
if row is nothing then
Dim Row = MyDataTable.rows.NewRow
Row("Form") = Frm.Name
Row("Property") = prop.Name
Row("Value") =prop.GetValue(Frm, Nothing)
rows.add(row)
else
Row("Value") =prop.GetValue(Frm, Nothing) 'Update Value
end if
Next
end sub
I wrote this code without test it.
I only intend to show concept.
Dim f as new Form2, Ty = Gettype(Form2) ' Ty = f.Gettype() - you can get Type from Object and also from class.
Restor3(Ty, f, MyTable)
F.ShowDialog
Save(Ty, f, MyTable)
Note that You need modify Save Method to allow Update:
Sub Save(FormType as Type, Frm As Form, MyTable as DataTable)
Dim properties = FormType.GetProperties 'Only Public Properties
Dim Key(1) as object
Key(0) = Frm.Name
For Each prop As PropertyInfo In properties
Key(1)= prop.Name
dim Row = MyTable.Rows.Find(key)
if row is nothing then
Dim Row = MyDataTable.rows.NewRow
Row("Form") = Frm.Name
Row("Property") = prop.Name
Row("Value") =prop.GetValue(Frm, Nothing)
rows.add(row)
else
Row("Value") =prop.GetValue(Frm, Nothing) 'Update Value
end if
Next
end sub
I wrote this code without test it.
I only intend to show concept.
ASKER
x77,
I figured out I was typing the code incorrectly. The code works, however what do I pass as FormType parameter. Is this the class or properties from the form I am passing?
I figured out I was typing the code incorrectly. The code works, however what do I pass as FormType parameter. Is this the class or properties from the form I am passing?
ASKER
X77,
OK. One question..
What if I am already on the form and placing a call to this subroutine? Would I still use the same code you gave as an example?
OK. One question..
What if I am already on the form and placing a call to this subroutine? Would I still use the same code you gave as an example?
ASKER
X77,
When I called this subroutine it was in a class that was declared from the Form. So I passed the Form name as Me to the class and just before the actual subroutine was called I created ty to hold the GetType of the form being passed and then the subroutine is executed. I get the following error:
Object type does not match target type".
The error seams to point directly to "GetValue(prop, Nothing)". Any ideas?
When I called this subroutine it was in a class that was declared from the Form. So I passed the Form name as Me to the class and just before the actual subroutine was called I created ty to hold the GetType of the form being passed and then the subroutine is executed. I get the following error:
Object type does not match target type".
The error seams to point directly to "GetValue(prop, Nothing)". Any ideas?
ASKER CERTIFIED SOLUTION
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ASKER
The solution was a bit hard to follow.
Dim myObject As Object = Me.TextBox1
Dim propertyName As String = "Text"
'To get the value
Dim propertyValue As String = CallByName(myObject, propertyName, CallType.Get) 'Or you can dim propertyValue As Object if you don't know the data type
'To set the value
CallByName(myObject, propertyName, CallType.Let, newValue)
Hope that helps.