Iterate Through Devexpres TextEdit Controls in VB.NET

Question

Could someone help iterating through DevExpress TextEdit controls within an XTRAFORM in vb.net?

What I am actually trying to do is to intercept any value changes at FormClosing event by using EditValue and OldEditValue properties.

I meight need to tell that my controls are contained in XtraTab and XtraPanel Containers.

the following is what I tried:

Public Function TextEditChangesOccured(frm As XtraForm) As Boolean
    Dim result As Boolean
    For Each ctrl As BaseEdit In frm.Controls
        If TypeOf ctrl Is TextEdit Then
            If ctrl.EditValue <> ctrl.OldEditValue Then
                result = True
            Else
                result = False
            End If
        End If
    Next
    Return result
End Function

 Private Sub MyXtraForm_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
    If TextEditChangesOccured(Me) Then
        DevExpress.XtraEditors.XtraMessageBox.Show("Changes have occured!", My.Application.Info.AssemblyName, MessageBoxButtons.OK, MessageBoxIcon.Information)
    End If
End Sub

but it says unable to cast XtraTab control to TextEdit control.

Your help will be much appreciated.

Answer 1

To make your code works just change your code snippet as follows:

Public Function TextEditChangesOccured(container As Control) As Boolean
    Dim result As Boolean
    For Each ctrl As Control In container.Controls
        Dim bEdit As BaseEdit = TryCast(ctrl, BaseEdit)
        If bEdit IsNot Nothing Then
            Dim tEdit As TextEdit = TryCast(ctrl, TextEdit)
            If tEdit IsNot Nothing Then
                result = result Or (bEdit.EditValue <> bEdit.OldEditValue)
            End If
        Else
            result = result Or TextEditChangesOccured(ctrl)
        End If
    Next
    Return result
End Function

To detect changes for all the editors within a Form use the following approach:

Partial Public Class Form1
    Inherits Form

    Public Sub New()
        InitializeComponent()
        SubscribeTextEditValueChanged(Me)
    End Sub
    Private Sub SubscribeTextEditValueChanged(ByVal container As Control)
        For Each ctrl As Control In container.Controls
            Dim tEdit As TextEdit = TryCast(ctrl, TextEdit)
            If tEdit IsNot Nothing Then
                AddHandler tEdit.EditValueChanged, AddressOf tEdit_EditValueChanged
            Else
                SubscribeTextEditValueChanged(ctrl)
            End If
        Next ctrl
    End Sub
    Private IsEditValueChanged As Boolean
    Private Sub tEdit_EditValueChanged(ByVal sender As Object, ByVal e As EventArgs)
        IsEditValueChanged = True
    End Sub
    Protected Overrides Sub OnClosing(ByVal e As CancelEventArgs)
        If IsEditValueChanged Then
            ' do some stuff
        End If
        MyBase.OnClosing(e)
    End Sub
End Class