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)

public:
[UIPermissionAttribute(SecurityAction::LinkDemand, Window = UIPermissionWindow::AllWindows)]
static void DrawReversibleFrame(
	Rectangle rectangle,
	Color backColor,
	FrameStyle style
)

Parameters

rectangle
Type: System.Drawing::Rectangle

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

backColor
Type: System.Drawing::Color

The Color of the background behind the frame.

style
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.

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);
   }

.NET Framework
Available since 1.1
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