Problem in opening model dialog window from worker thread

[Krrish]

Can any one help me out, I am trying to run a seperate thread from my main thread to perform some functionality, my problem is I am trying to open a modal dialog from my child thread, even I use Form.ShowDialog() method this is behaving as modeless and it is allowing access to other screens in the mdi which should be restriceted. Any help would be appreciated Regards, Krishna

[leppie]

You should not be creating controls on other threads. Use Control.Invoke() from you worker thread.**

xacc.ide-0.1.3.14 - Now with syntax support for PowerShell
xacc.ide-0.1.3.13 source code

**

[S Senthil Kumar]

To substantiate Leppie's post, when you call ShowDialog on a thread other than the UI thread, it essentially behaves as a modeless dialog. To do what you want, you have to make the call come from the UI thread, which you can do by calling Invoke[^] on the main form or any of the main form's controls. This will cause the delegate to be called from the UI thread and your form will be modal. Regards Senthil _____________________________ My Blog | My Articles | WinMacro

[Lost User]

e.g you have a method called ShowMyDialog(). You cannot call this method from another thread. Then you must use this code, if you want to call ShowMyDialog() from another thread :

MethodInvoker mInvoker = new MethodInvoker(ShowMyDialog);
Invoke(mInvoker);

[Krrish]

Can ypu pls explain it with a simple example Krishna

[Lost User]

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Threading;

namespace WindowsApplication5
{
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.Button button1;
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 );
	}

	private void InitializeComponent()
	{
		this.button1 = new System.Windows.Forms.Button();
		this.SuspendLayout();
		this.button1.Location = new System.Drawing.Point(48, 72);
		this.button1.Name = "button1";
		this.button1.TabIndex = 1;
		this.button1.Text = "Change text";
		this.button1.Click += new System.EventHandler(this.button1\_Click);
		this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
		this.ClientSize = new System.Drawing.Size(208, 189);
		this.Controls.Add(this.button1);
		this.Name = "Form1";
		this.Text = "Form1";
		this.ResumeLayout(false);
	}

	\[STAThread\]
	static void Main() 
	{	Application.Run(new Form1()); }

	private void button1\_Click(object sender, System.EventArgs e)
	{
		/\*\*\*\*\* WRONG \*\*\*\*\*/

// Thread t = new Thread(new ThreadStart(Run));
// t.Start();

		/\*\*\*\*\* OK \*\*\*\*\*\*/
		Thread t = new Thread(new ThreadStart(CreateNewLabel));
		t.Start();
	}

	private void CreateNewLabel()
	{
		MethodInvoker minvoker = new MethodInvoker(Run);
		Invoke(minvoker);
	}

	private void Run()
	{
		try
		{
			Label label = new Label();
			label.Name = "MyLabel";
			label.Text = "MyLabel";
			label.Location = new Point(50, 50);
			this.Controls.Add(label);
		}
		catch(Exception ex)
		{	MessageBox.Show(ex.ToString());	}
	}
}

}

You cannot call method "Run" directly, because method "Run" is in another thread. That's why you must call the method CreateNewLabel to create a new label from another thread. You can find the complete description in : http://www.oreilly.de/catalog/csharpnutger/chapter/ch04.html That site is in german, you can use www.google.com/translate to translate it in english.