How can I drag a bordeless window from any object in VB.NET?

Question

My form is set to bordeless, and I found code that allows me to drag the form around by simply clicking someone on the form and dragging the window about.

Dim IsDraggingForm As Boolean = False
Private MousePos As New System.Drawing.Point(0, 0)

Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles MyBase.MouseDown
    If e.Button = MouseButtons.Left Then
        IsDraggingForm = True
        MousePos = e.Location
    End If
End Sub

Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As MouseEventArgs) Handles MyBase.MouseUp
    If e.Button = MouseButtons.Left Then IsDraggingForm = False
End Sub

Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles MyBase.MouseMove
    If IsDraggingForm Then
        Dim temp As Point = New Point(Me.Location + (e.Location - MousePos))
        Me.Location = temp
        temp = Nothing
    End If
End Sub

The problem is that my form is mostly full of control objects such as Labels, and a ListBox that have no visible borders. Attempting to drag the window clicked on these control objects does not allow this.

This is UI design mistake. Your user will never figure out how the move the window. He's not going to click on a Label or ListBox, those are not controls that say "click me to drag the window". Somewhat inevitably, your code cannot figure it out either. Make it obvious, draw a caption. — Hans Passant, Sep 19 '15 at 16:22

score 0 · Accepted Answer · edited May 23 '17 at 11:58

0

A solution could be to enable KeyPreview and set a keyboard short-cut to enable moving the Form (you can use Control.MousePosition to follow the mouse) on the KeyDown event and release on KeyUp.

If you're definitely after moving everything with a Click, you can set a callback from using PInvoke ( Global mouse event handler ) checking the location of the mouse is within your Form area and the Form is in focus and then do the same job with Form.Location and Control.MousePosition.

edited May 23 '17 at 11:58

Community

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answered Sep 19 '15 at 16:18

Stefano d'Antonio

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Another simple example of global mouse handler (C#): http://stackoverflow.com/questions/804374/capturing-mouse-events-from-every-component-on-c-sharp-winform – Stefano d'Antonio Sep 19 '15 at 16:31
Thanks! This did exactly what I asked for. – daily001 Sep 20 '15 at 02:48

score 0 · Answer 2 · answered Sep 19 '15 at 16:22

Use the following code:- (After removing your code for dragging)

<DllImportAttribute("user32.dll")> _
Public Shared Function SendMessage(hWnd As IntPtr, Msg As Integer, wParam As Integer, lParam As Integer) As Integer
End Function
<DllImportAttribute("user32.dll")> _
Public Shared Function ReleaseCapture() As Boolean
End Function

Private Sub Object_MouseDown(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles <Object>.MouseDown
If e.Button = MouseButtons.Left Then
    ReleaseCapture()
    SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0)
End If

End Sub

Replace <Object> (8th Line, after 'Handles') with the name of the object you want as the handle for dragging.

How can I drag a bordeless window from any object in VB.NET?

2 Answers2