ControlPaint.DrawReversibleFrame(Rectangle, Color, FrameStyle) Method

public:
 static void DrawReversibleFrame(System::Drawing::Rectangle rectangle, System::Drawing::Color backColor, System::Windows::Forms::FrameStyle style);

public static void DrawReversibleFrame (System.Drawing.Rectangle rectangle, System.Drawing.Color backColor, System.Windows.Forms.FrameStyle style);

static member DrawReversibleFrame : System.Drawing.Rectangle * System.Drawing.Color * System.Windows.Forms.FrameStyle -> unit

Public Shared Sub DrawReversibleFrame (rectangle As Rectangle, backColor As Color, style As FrameStyle)

Parameters

Examples

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.

private:
   // 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.
   bool isDrag;
   Rectangle theRectangle;
   Point startPoint;
   void Form1_MouseDown( Object^ sender, System::Windows::Forms::MouseEventArgs^ e )
   {
      
      // 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 )
      {
         isDrag = true;
      }

      Control^ control = dynamic_cast<Control^>(sender);
      
      // Calculate the startPoint by using the PointToScreen 
      // method.
      startPoint = control->PointToScreen( Point(e->X,e->Y) );
   }

   void Form1_MouseMove( Object^ /*sender*/, System::Windows::Forms::MouseEventArgs^ e )
   {
      
      // If the mouse is being dragged, 
      // undraw and redraw the rectangle as the mouse moves.
      if ( isDrag )
      {
         ControlPaint::DrawReversibleFrame( theRectangle, this->BackColor, FrameStyle::Dashed );
         
         // Calculate the endpoint and dimensions for the new 
         // rectangle, again using the PointToScreen method.
         Point endPoint = this->PointToScreen( Point(e->X,e->Y) );
         int width = endPoint.X - startPoint.X;
         int height = endPoint.Y - startPoint.Y;
         theRectangle = Rectangle(startPoint.X,startPoint.Y,width,height);
         
         // Draw the new rectangle by calling DrawReversibleFrame
         // again.  
         ControlPaint::DrawReversibleFrame( theRectangle, this->BackColor, FrameStyle::Dashed );
      }
   }

   void Form1_MouseUp( Object^ /*sender*/, System::Windows::Forms::MouseEventArgs^ /*e*/ )
   {
      
      // 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, this->BackColor, FrameStyle::Dashed );
      
      // 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.
      Rectangle controlRectangle;
      for ( int i = 0; i < Controls->Count; i++ )
      {
         controlRectangle = Controls[ i ]->RectangleToScreen( Controls[ i ]->ClientRectangle );
         if ( controlRectangle.IntersectsWith( theRectangle ) )
         {
            Controls[ i ]->BackColor = Color::BurlyWood;
         }

      }
      
      // Reset the rectangle.
      theRectangle = Rectangle(0,0,0,0);
   }

// 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.

bool isDrag = false;
Rectangle theRectangle = new Rectangle(new Point(0, 0), new Size(0, 0));
Point startPoint;

private void Form1_MouseDown(object sender, 
    System.Windows.Forms.MouseEventArgs e)
{

    // 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)
    {
        isDrag = true;
    }

    Control control = (Control) sender;

    // Calculate the startPoint by using the PointToScreen 
    // method.
    startPoint = control.PointToScreen(new Point(e.X, e.Y));
}

private void Form1_MouseMove(object sender, 
    System.Windows.Forms.MouseEventArgs e)
{

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

        // Hide the previous rectangle by calling the 
        // DrawReversibleFrame method with the same parameters.
    {
        ControlPaint.DrawReversibleFrame(theRectangle, 
            this.BackColor, FrameStyle.Dashed);

        // Calculate the endpoint and dimensions for the new 
        // rectangle, again using the PointToScreen method.
        Point endPoint = ((Control) sender).PointToScreen(new Point(e.X, e.Y));

        int width = endPoint.X-startPoint.X;
        int height = endPoint.Y-startPoint.Y;
        theRectangle = new Rectangle(startPoint.X, 
            startPoint.Y, width, height);

        // Draw the new rectangle by calling DrawReversibleFrame
        // again.  
        ControlPaint.DrawReversibleFrame(theRectangle, 
            this.BackColor, FrameStyle.Dashed);
    }
}

private void Form1_MouseUp(object sender, 
       System.Windows.Forms.MouseEventArgs e)
{
    // 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, 
        this.BackColor, FrameStyle.Dashed);

    // 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.
    Rectangle controlRectangle;
    for(int i = 0; i < Controls.Count; i++)
    {
        controlRectangle = Controls[i].RectangleToScreen
            (Controls[i].ClientRectangle);
        if (controlRectangle.IntersectsWith(theRectangle))
        {
            Controls[i].BackColor = Color.BurlyWood;
        }
    }

    // Reset the rectangle.
    theRectangle = new Rectangle(0, 0, 0, 0);
}

' 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, _
            FrameStyle.Dashed)

        ' 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, _
             FrameStyle.Dashed)
    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, _
        FrameStyle.Dashed)

    ' 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 _
            (Controls(i).ClientRectangle)
        If controlRectangle.IntersectsWith(theRectangle) Then
            Controls(i).BackColor = Color.BurlyWood
        End If
    Next

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

Remarks

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.

Applies to

See also

• FrameStyle