I'm trying to create a new control deriving from ScrollableControl. Now I'd like to add a nice 3d-border around the entire control, but I can't seem to limit the area that the autoscroll feature uses so that it doesn't include the border. How do I do this?
public override Rectangle DisplayRectangle {
get {
int borderWidth = 3;
Rectangle clientRect = ClientRectangle;
Rectangle displayRect = new Rectangle(borderWidth, borderWidth, clientRect.Width - borderWidth, clientRect.Height - borderWidth);
return displayRect;
}
}
- mike
public class TestControl : ScrollableControl
{
private int borderWidth;
public TestControl()
{
borderWidth = 3;
}
public override Rectangle DisplayRectangle
{
get
{
Rectangle clientRect = base.DisplayRectangle;
Rectangle displayRect = new Rectangle(borderWidth, borderWidth, clientRect.Width - borderWidth, clientRect.Height - borderWidth);
return displayRect;
}
}
protected override void OnLayout(LayoutEventArgs e)
{
this.AutoScrollMinSize = new Size(400, 500);
base.OnLayout(e);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
Graphics g = e.Graphics;
Rectangle clip = e.ClipRectangle;
PaintBorder(g, clip);
}
protected void PaintBorder(Graphics g, Rectangle clip)
{
ControlPaint.DrawBorder3D(g,0,0,Width,Height,Border3DStyle.Sunken, Border3DSide.All);
}
}
I tried to put a breakpoint in the DisplayRectangle property, and it seems like it is actually never invoked..
/Anders
public TestControl()
{
this.SetStyle(ControlStyles.ResizeRedraw, true);
borderSize = new Size();
borderSize.Width = SystemInformation.VerticalScrollBarWidth;
borderSize.Height = SystemInformation.HorizontalScrollBarHeight;
}
protected override void OnLayout(LayoutEventArgs e)
{
this.AutoScrollMinSize = new Size(400, 500);
base.OnLayout(e);
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
Graphics g = e.Graphics;
Rectangle clip = e.ClipRectangle;
PaintBorder(g, clip);
}
protected void PaintBorder(Graphics g, Rectangle clip)
{
ControlPaint.DrawBorder3D(g,0,0,Width - borderSize.Width,Height - borderSize.Height,Border3DStyle.Sunken, Border3DSide.All);
}
}
- mike
What annoys me the most is that the Panel control somehow manages to do this (and it is, as far as I can see, derived from ScrollableControl). Perhaps I should simply swallow my pride and try to use Panel as the base class, but somehow it doesn't feel right.
So I went and looked at what our Panel does, and it relies on Windows to draw the border. Basically, just override CreateParams, call the base version to get a CreateParams object and then or in the WS_EX_CLIENTEDGE flag to the ExStyle property. This is for a 3d border. For a fixed border or in the WS_BORDER flag to the Style property.
I think this is your best bet, but honestly, it is a bit of reinventing the wheel. Panel is a very thin wrapper over ScrollableControl. It doesn't add much, and hence wouldn't add much weight. Unless you're a hardcore OO purist, the effort to draw borders yourself probably isn't worth the time.
- mike
