Richtextbox doubledlick and richtextbox resize causes text to be selected automatically.

What is wrong with using the DoubleClick() event?...

    Private Sub txtrichbxMemo_DoubleClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtrichbxMemo.DoubleClick
        Dim start As Integer = txtrichbxMemo.SelectionStart
        Dim length As Integer = txtrichbxMemo.SelectionLength

        MaximizeRichTextbox()

        txtrichbxMemo.SelectionStart = start
        txtrichbxMemo.SelectionLength = length
    End Sub

The above code stores the current selection start/length and then restores them after calling MaximizeRichTextbox().



On a side note, your original code could have been written as:

    Private Sub txtrichbxMemo_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles txtrichbxMemo.MouseDown
        Static lastclick As DateTime

        If lastclick <> Nothing Then
            Dim ts As TimeSpan = DateTime.Now.Subtract(lastclick)
            If ts.TotalMilliseconds < 500 Then
                Dim start As Integer = txtrichbxMemo.SelectionStart
                Dim length As Integer = txtrichbxMemo.SelectionLength

                MaximizeRichTextbox()

                txtrichbxMemo.SelectionStart = start
                txtrichbxMemo.SelectionLength = length
            End If
        End If

        lastclick = DateTime.Now
    End Sub

The richtextbox control in visual basic.net does not have a doubleclick event..    i have been trying to create one with using addhandler with no luck.

Also, the code above does not solve the original problem.   When the richtextbox is maximized, some of the text still becomes selected (highlighted)

You must have VB.Net 2003 (or below)?  There is in fact a DoubleClick() event for the RichTextBox in VB.Net 2005.

Really can't give you any further advice then without seeing more code!

Show us your MaximizeRichTextbox() sub please so we can get a better idea what is happening...

By the way, here is one way to trap a DoubleClick in a RTB in VB.Net 2003:

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private WithEvents myRtbHandler As RtbHandler

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        myRtbHandler = New RtbHandler(Me.txtrichbxMemo)
    End Sub

    Private Sub myRtbHandler_RtbDoubleClicked(ByVal RTB As System.Windows.Forms.RichTextBox) Handles myRtbHandler.RtbDoubleClicked
        Debug.WriteLine("RTB was Double Clicked")
    End Sub

    Private Class RtbHandler
        Inherits NativeWindow

        Private Const WM_LBUTTONDBLCLK As Integer = &H203
        Private RTB As RichTextBox

        Public Event RtbDoubleClicked(ByVal RTB As RichTextBox)

        Public Sub New(ByVal RTB As RichTextBox)
            If Not (RTB Is Nothing) Then
                Me.RTB = RTB
                Me.AssignHandle(RTB.Handle)
            End If
        End Sub

        Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
            Select Case m.Msg
                Case WM_LBUTTONDBLCLK
                    RaiseEvent RtbDoubleClicked(Me.RTB)

            End Select

            MyBase.WndProc(m)
        End Sub

    End Class

End Class

Here...made a slight modification to the WndProc() above and the default behaviour for the DoubleClick() even has been suppressed:

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private WithEvents myRtbHandler As RtbHandler

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        myRtbHandler = New RtbHandler(Me.txtrichbxMemo)
    End Sub

    Private Sub myRtbHandler_RtbDoubleClicked(ByVal RTB As System.Windows.Forms.RichTextBox) Handles myRtbHandler.RtbDoubleClicked
        Debug.WriteLine("Double Click on RTB")
        MaximizeRichTextbox()
    End Sub

    Private Sub MaximizeRichTextbox()
        Debug.WriteLine("MaximizeRichTextbox()")
    End Sub

    Private Class RtbHandler
        Inherits NativeWindow

        Private Const WM_LBUTTONDBLCLK As Integer = &H203
        Private RTB As RichTextBox

        Public Event RtbDoubleClicked(ByVal RTB As RichTextBox)

        Public Sub New(ByVal RTB As RichTextBox)
            If Not (RTB Is Nothing) Then
                Me.RTB = RTB
                Me.AssignHandle(RTB.Handle)
            End If
        End Sub

        Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
            Select Case m.Msg
                Case WM_LBUTTONDBLCLK
                    RaiseEvent RtbDoubleClicked(Me.RTB)
                    Exit Sub ' suppress default behaviour

            End Select

            MyBase.WndProc(m)
        End Sub

    End Class

End Class

You were exactly right.  I am using VB.Net 2003.

And of course,  your solution works perfectly.    Thank you .

PS... Is there a significant advantage to moving up to the latest version of VB.Net?