why the exeption appier

Akmal Ali

15y14.8kGDI+

Hi.
My name is Akmal. And I try to use C# for my job. I need to draw some images on PictureBox control. This is code:

 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace test_Move_Image
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Image map;
Bitmap bmp;
private void button1_Click(object sender, EventArgs e)
{
Image img = Image.FromFile(@"c:\MAP_TAS\wash.jpg");
Bitmap tbmp = new Bitmap(img.Width, img.Height);
Graphics tgr = Graphics.FromImage(tbmp);
tgr.DrawImage(img, 0, 0);
map = tbmp;
draw_map();
tgr.Dispose();
tbmp.Dispose();
}
private void draw_map()
{
pictureBox1.Image = null;
pictureBox1.Image = map;
GC.Collect();
GC.WaitForPendingFinalizers();
}

}
}

Try to run this code and you will see the erorr. But i don't uderstand where the problem in my code?
Please help me.

11 Replies

Know the answer? Post it — somebody with the same question will find it here.

Suthish Nair15y ago
If your query got resolved, then accept the post that helped you as Answer.
Akmal Ali15y ago

Thank's a lot Frogleg. I have tried your code and the problem has disappeared.
Thank's to all for your assistance and for your attention.
Sam Hobbs15y ago
I think Frogleg is much more experienced with graphics than I am; do as he says.
Frogleg15y ago

instead of
map = tbmp;
use
Rectangle rct = new Rectangle(0,0,tbmp.Width,tbmp.Height);
map = tbmp.Clone(rct, tbmp.PixelFormat);
if map is equal to tbmp and tbmp is disposed - map = null
Sam Hobbs15y ago
I think the question is why you are doing that; why are you disposing the object? I think there is no reason to do it.

You did not say if you understand about Paint. I think the answer to the question of why you are getting the error is that Windows needs the object to do the Paint. If you don't understand about painting in Windows then you need to learn about that.

Here is a simple rule. Don't call Dispose unless you know you need it.
Akmal Ali15y ago
Yes, you're right. I commented out the line "tbmp.Dispose();" and the program is no longer report an error. But perhaps someone can explain why it happening (this error)?
Sam Hobbs15y ago
So the error is occurring when the program is doing a Paint; do you understand what I mean by that?

When I remove (comment out) the lines that call tgr.Dispose() and tbmp.Dispose() then the error is gone. I am not experienced with graphics in .Net but I really doubt that you need to call Dispose for those two objects; it is probably just a problem to call Dispose for them.
Akmal Ali15y ago
Here is the error message. Error occurs when you run "Application.Run (new Form1 ());". I use Russian version of VS2008. Therefore, not sure what the error message will be clear to you.
Below I will show the error message and a screen shot.
/*
System.ArgumentException ?? ??????????
Message="???????????? ????????."
Source="System.Drawing"
StackTrace:
? System.Drawing.Image.get_Width()
? System.Drawing.Image.get_Size()
? System.Windows.Forms.PictureBox.ImageRectangleFromSizeMode(PictureBoxSizeMode mode)
? System.Windows.Forms.PictureBox.OnPaint(PaintEventArgs pe)
? System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
? System.Windows.Forms.Control.WmPaint(Message& m)
? System.Windows.Forms.Control.WndProc(Message& m)
? System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
? System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
? System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
? System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
? System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
? System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
? System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
? System.Windows.Forms.Application.Run(Form mainForm)
? test_Move_Image.Program.Main() ? C:\Documents and Settings\?????????????\??? ?????????\Visual Studio 2008\Projects\test_Move_Image\test_Move_Image\Program.cs:?????? 18
? System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
? System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
? Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
? System.Threading.ThreadHelper.ThreadStart_Context(Object state)
? System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
? System.Threading.ThreadHelper.ThreadStart()
InnerException:
*/
Sam Hobbs15y ago
It is good that you have provided code that can reproduce the error, but you are more likely to get help if you tell us what the error message is and what line of code is getting the error.
Suthish Nair15y ago
what error you getting?
Prasant Jinaga15y ago

Hi Akmal,
Put the image in solution explorer and try..Hope it will work.
Thanks,
Prasant