Rectangle/OnPaint Error in 2005

[=?Utf-8?B?Unlhbg==?=]

Why do I sometimes get this error; works fine most of the time:
Rectangle '{X=0,Y=0,Width=0,Height=0}' cannot have a width or height equal
to 0
void OnPaint(Object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy, Color.Chocolate, LinearGradientMode.ForwardDiagonal);
g.FillRectangle(gradientBrush, r);
}

[Peter Duniho]

On Fri, 15 Aug 2008 17:47:12 -0700, Ryan <Ry**@discussions.microsoft.com>
wrote:

Why do I sometimes get this error; works fine most of the time:
Rectangle '{X=0,Y=0,Width=0,Height=0}' cannot have a width or height
equal
to 0

When do you get the error? What line of code causes it? Can you post a
concise-but-complete code sample that reliably reproduces the problem?

AFAIK Graphics.FillRectangle has no limitation on using an empty
Rectangle. But as near as I can tell, LinearGradientBrush does. If you
pass it an empty rectangle, it will throw the exception you describe.

I don't know why you have a control instance that is empty when it tries
to paint itself, but the solution would be to either not let it have an
empty rectangle as its dimensions, or to check the rectangle in the
OnPaint() method and just not try to draw anything if the ClientRectangle
is empty.

Pete

[=?Utf-8?B?Unlhbg==?=]

Peter,
The following line produces the error

LinearGradientBrush gradientBrush = new LinearGradientBrush(r, Color.Navy,
Color.Chocolate, LinearGradientMode.ForwardDiagonal);

Complete code:

void OnPaint(Object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy, Color.Chocolate, LinearGradientMode.ForwardDiagonal);
g.FillRectangle(gradientBrush, r);
}

"Peter Duniho" wrote:

On Fri, 15 Aug 2008 17:47:12 -0700, Ryan <Ry**@discussions.microsoft.com>
wrote:

Why do I sometimes get this error; works fine most of the time:
Rectangle '{X=0,Y=0,Width=0,Height=0}' cannot have a width or height
equal
to 0

When do you get the error? What line of code causes it? Can you post a
concise-but-complete code sample that reliably reproduces the problem?

AFAIK Graphics.FillRectangle has no limitation on using an empty
Rectangle. But as near as I can tell, LinearGradientBrush does. If you
pass it an empty rectangle, it will throw the exception you describe.

I don't know why you have a control instance that is empty when it tries
to paint itself, but the solution would be to either not let it have an
empty rectangle as its dimensions, or to check the rectangle in the
OnPaint() method and just not try to draw anything if the ClientRectangle
is empty.

Pete

[Peter Duniho]

On Mon, 18 Aug 2008 07:24:04 -0700, Ryan <Ry**@discussions.microsoft.com>
wrote:

Peter,
The following line produces the error

LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy,
Color.Chocolate, LinearGradientMode.ForwardDiagonal);

Well, since I'd already guessed that, I can't say that adds much.

Complete code:

void OnPaint(Object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy, Color.Chocolate, LinearGradientMode.ForwardDiagonal);
g.FillRectangle(gradientBrush, r);
}

That's not complete code. Please see Jon Skeet's discussion on the topic
of code samples, both complete and incomplete:
http://www.yoda.arachsys.com/csharp/complete.html
http://www.yoda.arachsys.com/csharp/incomplete.html

In any case, I believe that my previous reply included enough information
to help you fix the problem. Was there something about that reply you
didn't understand?

Pete

[=?Utf-8?B?Unlhbg==?=]

Peter,
Your previous reply had given me enough information but I posted the OnPaint
method for your reference to get moer info.
The error is interminent and very difficult to reproduce; I have added the
follo
Thanks for your help.

I have modified the code as follows:
void OnPaint(Object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
if (!r.IsEmpty)
{
LinearGradientBrush gradientBrush = new
LinearGradientBrush(r, Color.Navy, Color.Chocolate,
LinearGradientMode.ForwardDiagonal);
g.FillRectangle(gradientBrush, r);
}
}
"Peter Duniho" wrote:

On Mon, 18 Aug 2008 07:24:04 -0700, Ryan <Ry**@discussions.microsoft.com>
wrote:

Peter,
The following line produces the error

LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy,
Color.Chocolate, LinearGradientMode.ForwardDiagonal);

Well, since I'd already guessed that, I can't say that adds much.

Complete code:

void OnPaint(Object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
LinearGradientBrush gradientBrush = new LinearGradientBrush(r,
Color.Navy, Color.Chocolate, LinearGradientMode.ForwardDiagonal);
g.FillRectangle(gradientBrush, r);
}

That's not complete code. Please see Jon Skeet's discussion on the topic
of code samples, both complete and incomplete:
http://www.yoda.arachsys.com/csharp/complete.html
http://www.yoda.arachsys.com/csharp/incomplete.html

In any case, I believe that my previous reply included enough information
to help you fix the problem. Was there something about that reply you
didn't understand?

Pete