After my signature you'll find a simple control and a designer that reacts
to mouse clicks and movements at desighn time. You will be able to use these
principles to do what you want, I think .
--
Bob Powell [MVP]
Visual C#, System.Drawing
Ramuseco Limited .NET consulting
http://www.ramuseco.com
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using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
using System.Windows.Forms.Design;
namespace WellFormed
{
/// <summary>
/// Summary description for FilledGroupBox.
/// </summary>
[Designer(typeof(FilledGroupBoxDesigner))]
public class FilledGroupBox : GroupBox
{
Color _innerColor=Color.CadetBlue;
public Color InnerColor
{
get{return _innerColor;}
set{
_innerColor=value;
Invalidate();
}
}
Color _outerColor=Color.Wheat;
public Color OuterColor
{
get{return _outerColor;}
set{
_outerColor=value;
Invalidate();
}
}
Point _focusPoint=new Point(50,50);
public Point FocusPoint
{
get{return _focusPoint;}
set{
_focusPoint=value;
Invalidate();
}
}
public FilledGroupBox()
{
}
protected override void OnPaintBackground(PaintEventArgs pevent)
{
GraphicsPath pth=new GraphicsPath();
pth.AddRectangle(this.ClientRectangle);
PathGradientBrush pgb=new PathGradientBrush(pth);
pgb.CenterColor=this.InnerColor;
pgb.SurroundColors=new Color[]{this.OuterColor};
pgb.CenterPoint=this.FocusPoint;
pevent.Graphics.FillRectangle(pgb,this.ClientRectangle);
pgb.Dispose();
pth.Dispose();
}
}
public class FilledGroupBoxDesigner : ControlDesigner
{
//True when the mouse is down
bool _mouseDown;
//True when the mouse is in the grab-handle.
bool _inGrabber;
//Called when the designer is initialized
public override void Initialize(IComponent component)
{
base.Initialize (component);
//adds handlers to the mouse events of the control
this.Control.MouseDown+=new MouseEventHandler(Control_MouseDown);
this.Control.MouseUp+=new MouseEventHandler(Control_MouseUp);
this.Control.MouseMove+=new MouseEventHandler(Control_MouseMove);
}
protected override void Dispose(bool disposing)
{
//removes handlers from the mouse events of the control
this.Control.MouseDown-=new MouseEventHandler(Control_MouseDown);
this.Control.MouseUp-=new MouseEventHandler(Control_MouseUp);
this.Control.MouseMove-=new MouseEventHandler(Control_MouseMove);
base.Dispose (disposing);
}
protected override void OnPaintAdornments(PaintEventArgs pe)
{
//paints the grab-handle over the focus point.
base.OnPaintAdornments (pe);
FilledGroupBox fgb=(FilledGroupBox)this.Control;
pe.Graphics.FillRectangle(Brushes.White,fgb.FocusPoint.X-4,fgb.FocusPoint.Y-4,8,8);
pe.Graphics.DrawRectangle(Pens.Black,fgb.FocusPoint.X-4,fgb.FocusPoint.Y-4,8,8);
}
protected override bool GetHitTest(Point point)
{
//checks to see if the point is in the grab-handle
FilledGroupBox fgb=(FilledGroupBox)this.Control;
Point pnt=fgb.PointToClient(point);
Rectangle rc=new Rectangle(fgb.FocusPoint.X-4,fgb.FocusPoint.Y-4,8,8);
if(rc.Contains(pnt))
{
_inGrabber=true;
return true;
}
_inGrabber=false;
return base.GetHitTest (point);
}
protected override void OnSetCursor()
{
if(_inGrabber)
Control.Cursor=Cursors.Hand;
else
base.OnSetCursor ();
}
private void Control_MouseDown(object sender, MouseEventArgs e)
{
_mouseDown=true;
}
private void Control_MouseUp(object sender, MouseEventArgs e)
{
_mouseDown=false;
}
private void Control_MouseMove(object sender, MouseEventArgs e)
{
if(_mouseDown)
{
//modifies the value in the control
FilledGroupBox fgb=(FilledGroupBox)this.Control;
MemberDescriptor
md=TypeDescriptor.GetProperties(fgb,null)["FocusPoint"];
PropertyDescriptor pd=md as PropertyDescriptor;
Point oldPoint=(Point)pd.GetValue(fgb);
if(pd!=null)
pd.SetValue(fgb,new Point(e.X,e.Y));
//update the designer host and the property grid
this.RaiseComponentChanging(md);
this.RaiseComponentChanged(md,oldPoint,new Point(e.X,e.Y));
fgb.Invalidate();
}
}
}
}
