One cool, and not quite new, feature of Visual Studio 2005 is data binding to your own business objects. Just create a new business object class, add a property, add it to the Data Sources window as an object data source and drag it onto your form. Simple as that and you are good to go.
However as usual there is a gotcha :-(
It throw an exception in a property get or get during the data binding the exception is eaten by the DataBindings object. There are two ways around this, either pass False as the formattingEnabled parameters or add an event handler to the BindingComplete event and check for the Exception property being set.
The first option seems the easiest but isn’t :-( Even if you set the Format type to no formatting in the Formatting and Advanced Binding dialog the formattingEnabled will still be true.
That leaves the second option. To handle the BindingComplete event you need to ass an event handler to all Binding objects on the form. Not difficult once you have a reference to all controls. The following code does just that.
Public
Class Form1
Private Sub
Form1_Load(ByVal sender
As System.Object,
ByVal e As System.EventArgs)
Handles MyBase.Load
For
Each control As
Control In GetAllControls(Me)
For
Each binding As
Binding In control.DataBindings
AddHandler
binding.BindingComplete, AddressOf
BindingCompleteHandler
Next
Next
End
Sub
Private Sub
BindingCompleteHandler(ByVal sender
As Object,
ByVal e As
BindingCompleteEventArgs)
If e.Exception
IsNot Nothing
Then
Throw
New Exception("Unhandled
exception during databinding actions.", e.Exception)
End
If
End Sub
Private
Function GetAllControls(ByVal container
As Control) As
List(Of Control)
Dim result
As New List(Of
Control)
Dim pos
As Integer =
0
result.Add(container)
Do
While pos < result.Count
For
Each control As
Control In result(pos).Controls
result.Add(control)
Next
pos += 1
Loop
Return
result
End
Function
End
Class
Public
Class SomeData
Private _lastName
As String =
"Maurice de Beijer"
Public
Property LastName()
As String
Get
Throw
New Exception("Get:
" + _lastName)
Return _lastName
End
Get
Set(ByVal
value As String)
_lastName = value
End
Set
End
Property
End
Class
