DrawReversibleFrame Method

ControlPaint.DrawReversibleFrame Method (Rectangle, Color, FrameStyle)


Draws a reversible frame on the screen within the specified bounds, with the specified background color, and in the specified state.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

<UIPermissionAttribute(SecurityAction.LinkDemand, Window := UIPermissionWindow.AllWindows)>
Public Shared Sub DrawReversibleFrame (
	rectangle As Rectangle,
	backColor As Color,
	style As FrameStyle


Type: System.Drawing.Rectangle

The Rectangle that represents the dimensions of the rectangle to draw, in screen coordinates.

Type: System.Drawing.Color

The Color of the background behind the frame.

Type: System.Windows.Forms.FrameStyle

One of the FrameStyle values that specifies the style of the frame.

The backColor parameter is used to calculate the fill color of the frame so that it is always visible against the background.

The results of this method can be reversed by drawing the same frame again. Drawing a frame using this method is similar to inverting a region of the screen, except that it provides better performance for a wider variety of colors.

The following code example demonstrates how to use the Control.RectangleToScreen, Control.PointToScreen, and the DrawReversibleFrame members. To run the example, paste the following code in a form called Form1 containing several controls. This example requires that the mouse events are connected to the event handlers defined in the example.

' The following three methods will draw a rectangle and allow 
' the user to use the mouse to resize the rectangle.  If the 
' rectangle intersects a control's client rectangle, the 
' control's color will change.

Dim isDrag As Boolean = False
Dim theRectangle As New rectangle(New Point(0, 0), New Size(0, 0))
Dim startPoint As Point

Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
    System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown

    ' Set the isDrag variable to true and get the starting point 
    ' by using the PointToScreen method to convert form coordinates to
    ' screen coordinates.
    If (e.Button = MouseButtons.Left) Then
        isDrag = True
    End If

    Dim control As Control = CType(sender, Control)

    ' Calculate the startPoint by using the PointToScreen 
    ' method.
    startPoint = control.PointToScreen(New Point(e.X, e.Y))
End Sub

Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove

    ' If the mouse is being dragged, undraw and redraw the rectangle
    ' as the mouse moves.
    If (isDrag) Then

        ' Hide the previous rectangle by calling the DrawReversibleFrame 
        ' method with the same parameters.
        ControlPaint.DrawReversibleFrame(theRectangle, Me.BackColor, _

        ' Calculate the endpoint and dimensions for the new rectangle, 
        ' again using the PointToScreen method.
        Dim endPoint As Point = CType(sender, Control).PointToScreen(New Point(e.X, e.Y))
        Dim width As Integer = endPoint.X - startPoint.X
        Dim height As Integer = endPoint.Y - startPoint.Y
        theRectangle = New Rectangle(startPoint.X, startPoint.Y, _
            width, height)

        ' Draw the new rectangle by calling DrawReversibleFrame again.  
        ControlPaint.DrawReversibleFrame(theRectangle, Me.BackColor, _
    End If
End Sub

Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As _
System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp

    ' If the MouseUp event occurs, the user is not dragging.
    isDrag = False

    ' Draw the rectangle to be evaluated. Set a dashed frame style 
    ' using the FrameStyle enumeration.
    ControlPaint.DrawReversibleFrame(theRectangle, Me.BackColor, _

    ' Find out which controls intersect the rectangle and change their color.
    ' The method uses the RectangleToScreen method to convert the 
    ' Control's client coordinates to screen coordinates.
    Dim i As Integer
    Dim controlRectangle As Rectangle
    For i = 0 To Controls.Count - 1
        controlRectangle = Controls(i).RectangleToScreen _
        If controlRectangle.IntersectsWith(theRectangle) Then
            Controls(i).BackColor = Color.BurlyWood
        End If

    ' Reset the rectangle.
    theRectangle = New Rectangle(0, 0, 0, 0)
End Sub

.NET Framework
Available since 1.1
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