C# Signature:

[DllImport("user32.dll")]
static extern bool ReleaseCapture();

VB.NET Signature:

<DllImport("user32.dll")> _
Private Shared Function ReleaseCapture() As Boolean
End Function

User-Defined Types:

None.

Notes:

None.

ReleaseCapture will delegate mousedown events to underlying controls.

Tips & Tricks:

Please add some!

Sample Code:

You can use the ReleaseCapture() function to provide drag functionality. for example the following code will allow the user to drag a control around a form (you'll have to assign this code to the mousedown event):

[DllImport("User32.dll")]
private static extern int SendMessage(IntPtr hWnd, int msg , int wParam , ref int lParam);
[DllImport("user32")]
public static extern int ReleaseCapture(IntPtr hwnd);

private const int WM_SYSCOMMAND = 0x112;
private const int MOUSE_MOVE = 0xF012;

private void control_MouseDown(object sender, MouseEventArgs e)
{
   Control ctrl = sender as Control;
   ReleaseCapture(ctrl.Handle);
   int nul =0;
   SendMessage(ctrl.Handle, WM_SYSCOMMAND, MOUSE_MOVE, ref nul);
  }

Alternative Managed API:

Capture property on System.Windows.Forms.Control

Do you know one? Please contribute it!

Public Class Form1

    Private MouseDown1 As Boolean
    Private PosDiff As Point

    Private Sub Form1_Load(ByVal sender As Object, _
           ByVal e As System.EventArgs) Handles Me.Load
    Me.TopMost = True
    End Sub
    Private Sub PictureBox3_MouseMove(ByVal sender As Object, ByVal e As  _
       System.Windows.Forms.MouseEventArgs) Handles PictureBox3.MouseMove
    If Not MouseDown1 Then Exit Sub
    If Not System.Windows.Forms.SystemInformation.MouseButtonsSwapped() Then
        If Not e.Button = Windows.Forms.MouseButtons.Left Then Exit Sub
    Else
        If Not e.Button = Windows.Forms.MouseButtons.Right Then Exit Sub
    End If
    Me.Location = New Point(Cursor.Position().X - PosDiff.X, Cursor.Position().Y - PosDiff.Y)
    End Sub

    Private Sub PictureBox3_MouseUp(ByVal sender As Object, ByVal e As  _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox3.MouseUp
    MouseDown1 = False
    End Sub

    Private Sub PictureBox3_MouseDown(ByVal sender As Object, ByVal e As  _
     System.Windows.Forms.MouseEventArgs) Handles PictureBox3.MouseDown
    MouseDown1 = True
    PosDiff = New Point(Cursor.Position().X - Me.Location.X, Cursor.Position().Y - Me.Location.Y)
    End Sub

End Class

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