RE: Dotnet dismantles my exceptions!!!

Tech-Archive recommends: Fix windows errors by optimizing your registry

From: tony lock (tonylock_at_discussions.microsoft.com)
Date: 10/07/04 

Date: Thu, 7 Oct 2004 06:57:06 -0700

What were you expecting, if it was "Useful Message", then I suggest that you
replace e.Exception.ToString() by e.Exception.Message in your MessageBox.

"Martin" wrote:

> This simple code has two button handlers, one throws an exception, the
> other asynchronously throws an exception. Each thrown exception has an
> outer and inner part, the first exception thrown shows a message box
> that says 'ApplicationException: Useful message -->
> DivideByZeroException: Attempted to divide by zero' and then a stack
> trace, the asynchronous throw produces a messagebox which says
> 'DivideByZeroException: Attempted to divide by zero'. This begs the
> obvious question, in the asynchronous throw what has happened to the
> exception I threw, how do I get it back, and how do I write exception
> safe code when I have to expect that any exception I throw will be
> dismantled before I ever get a chance to handle it?
>
> using System;
> using System.Threading;
> using System.Windows.Forms;
>
> namespace ExceptionTest2
> {
> public class Form1 : System.Windows.Forms.Form
> {
> private System.Windows.Forms.Button button1;
> private System.Windows.Forms.Button button2;
> private System.ComponentModel.Container components = null;
>
> public Form1()
> {
> InitializeComponent();
> }
>
> protected override void Dispose( bool disposing )
> {
> if(disposing)
> {
> if(components != null)
> {
> components.Dispose();
> }
> }
> base.Dispose( disposing );
> }
>
> #region Windows Form Designer generated code
> /// <summary>
> /// Required method for Designer support - do not modify
> /// the contents of this method with the code editor.
> /// </summary>
> private void InitializeComponent()
> {
> this.button1 = new System.Windows.Forms.Button();
> this.button2 = new System.Windows.Forms.Button();
> this.SuspendLayout();
>
> this.button1.Location = new System.Drawing.Point(96, 24);
> this.button1.Name = "button1";
> this.button1.Size = new System.Drawing.Size(88, 48);
> this.button1.TabIndex = 0;
> this.button1.Text = "button1";
> this.button1.Click += new
> System.EventHandler(this.button1_Click);
>
> this.button2.Location = new System.Drawing.Point(96, 96);
> this.button2.Name = "button2";
> this.button2.Size = new System.Drawing.Size(88, 48);
> this.button2.TabIndex = 1;
> this.button2.Text = "button2";
> this.button2.Click += new
> System.EventHandler(this.button2_Click);
>
> this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
> this.ClientSize = new System.Drawing.Size(292, 266);
> this.Controls.Add(this.button2);
> this.Controls.Add(this.button1);
> this.Name = "Form1";
> this.Text = "Form1";
> this.ResumeLayout(false);
> }
> #endregion
>
> [STAThread]
> static void Main()
> {
> Application.ThreadException += new
> ThreadExceptionEventHandler(OnThreadException);
> Application.Run(new Form1());
> }
>
> private static void OnThreadException(object sender,
> ThreadExceptionEventArgs e)
> {
> MessageBox.Show(e.Exception.ToString());
> }
>
> private void button1_Click(object sender, System.EventArgs e)
> {
> int a = 0;
>
> try
> {
> int b = 1 / a;
> }
> catch(System.DivideByZeroException ex)
> {
> throw new ApplicationException("Useful message", ex);
> }
> }
>
> private void button2_Click(object sender, System.EventArgs e)
> {
> BeginInvoke(new VoidDlg(AsyncThrow));
> }
>
> private void AsyncThrow()
> {
> int a = 0;
>
> try
> {
> int b = 1 / a;
> }
> catch(System.DivideByZeroException ex)
> {
> throw new ApplicationException("Useful message", ex);
> }
> }
> }
>
> delegate void VoidDlg();
> }
>

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