Winforms MDI “Desktop” Area Boundry

问题

The default MDI parent control has a large "desktop" area that can display multiple child forms. Users can drag forms to the edge of this desktop area so that most of the child form is off the screen. (A scroll bar then appears in the MDI parent) I don't like this feature. Is there a way to lock down the edge of the desktop area so that the child forms remain fully visible?

回答1:

Disable the MDI window scrollbars
Hook the OnMove event of all child windows. If the window is moved outside the boundary, "pop" it back along the x and y until it is back inside the parent.

回答2:

The code I used to implement the answer I selected above:

Public alreadyMoved As Boolean = False
Public Const HEIGHT_OF_MENU_STATUS_BARS As Integer = 50
Public Const WIDTH_OF_MENU_STATUS_BARS As Integer = 141
Private Sub Form_Move(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles MyBase.Move
    If Not alreadyMoved Then
        alreadyMoved = True

        'If I'm over the right boundry, drop back to right against that edge
        If Me.Location.X + Me.Width > _
            MdiParent.ClientRectangle.Width - WIDTH_OF_MENU_STATUS_BARS Then
            MyBase.Location = New System.Drawing.Point( _
                (MdiParent.ClientRectangle.Width - Me.Width - _
                WIDTH_OF_MENU_STATUS_BARS), MyBase.Location.Y)
        End If

        'If I'm over the bottom boundry, drop back to right against that edge
        If Me.Location.Y + Me.Height > _
            MdiParent.ClientRectangle.Height - HEIGHT_OF_MENU_STATUS_BARS Then
            MyBase.Location = New System.Drawing.Point( _
                MyBase.Location.X, (MdiParent.ClientRectangle.Height - _
                Me.Height - HEIGHT_OF_MENU_STATUS_BARS))
        End If

        'If I'm over the top boundry, drop back to the edge
        If Me.Location.Y < 0 Then
            MyBase.Location = New System.Drawing.Point(MyBase.Location.X, 0)
        End If

        'If I'm over the left boundry, drop back to the edge
        If Me.Location.X < 0 Then
            MyBase.Location = New System.Drawing.Point(0, MyBase.Location.Y)
        End If
    End If
    alreadyMoved = False
End Sub

回答3:

To clarify, what you say is the "desktop" area of the MDI client is the client area.

You could handle the resize/move event handlers of the child forms and then resize/restrict the movement of the child when it exceeds the bounds of the MDI client area.

来源：https://stackoverflow.com/questions/603412/winforms-mdi-desktop-area-boundry

标签

vb.net

winforms

mdi

mdiparent

mdichild