dispatch

  • Thread starter Thread starter Jhon
  • Start date Start date
J

Jhon

Hi,

How can I dispatch something from a worker thread to the UI thread ?

Thanks in advance
greetings
 
Jhon said:
Hi,

How can I dispatch something from a worker thread to the UI thread ?

Thanks in advance
greetings
Click to expand...


Read about Form.Invoke. The following code should give you the idea:

public class Foo
{
public MyFormClass TheForm; //has a TextBox called textBox; inherits
//from System.Windows.Forms.Form

public delegate void UIMessageHandler(String msg);
public static UIMessageHandler OnUIMsgProxy;



public Foo(MyFormClass form)
{

OnUIMsgProxy = new UIMessageHandler(OnUIMsg);
TheForm = form;
}

public static void OnUIMsg(String msg) //invoked on UI thread
{
//add new msg to the top of the current text
String curText = TheForm.textBox.Text;
if (curText.Length > 28000)
curText = curText.Substring(0,25000);
TheForm.textBox.Text = msg + "\r\n" + curText;
TheForm.textBox.Refresh();
}


/*
To insert text to the UI from another thread, the other thread calls:
Foo.UIMsgInvoke("here is some text for the UI");
/*


public static void UIMsgInvoke(String str)
{
//invoke the message writer on the UI thread
Object [] msg = new Object[1];
msg[0] = str;

if (TheForm.IsHandleCreated)
TheForm.Invoke(OnUIMsgProxy, msg);

}
}
 
that will do it,
Thanks,
Greetings

Fred Mellender said:
Jhon said:
Hi,

How can I dispatch something from a worker thread to the UI thread ?

Thanks in advance
greetings
Click to expand...


Read about Form.Invoke. The following code should give you the idea:

public class Foo
{
public MyFormClass TheForm; //has a TextBox called textBox; inherits
//from System.Windows.Forms.Form

public delegate void UIMessageHandler(String msg);
public static UIMessageHandler OnUIMsgProxy;



public Foo(MyFormClass form)
{

OnUIMsgProxy = new UIMessageHandler(OnUIMsg);
TheForm = form;
}

public static void OnUIMsg(String msg) //invoked on UI thread
{
//add new msg to the top of the current text
String curText = TheForm.textBox.Text;
if (curText.Length > 28000)
curText = curText.Substring(0,25000);
TheForm.textBox.Text = msg + "\r\n" + curText;
TheForm.textBox.Refresh();
}


/*
To insert text to the UI from another thread, the other thread calls:
Foo.UIMsgInvoke("here is some text for the UI");
/*


public static void UIMsgInvoke(String str)
{
//invoke the message writer on the UI thread
Object [] msg = new Object[1];
msg[0] = str;

if (TheForm.IsHandleCreated)
TheForm.Invoke(OnUIMsgProxy, msg);

}
}
Click to expand...
 
Fred Mellender said:
Read about Form.Invoke. The following code should give you the idea:
Click to expand...

<snip>

Just to be a bit more precise, it's not Form.Invoke but Control.Invoke.
This is handy as it means you don't need to find out which form a
control belongs to before invoking something on its UI thread.
 
Jon Skeet said:
<snip>

Just to be a bit more precise, it's not Form.Invoke but Control.Invoke.
This is handy as it means you don't need to find out which form a
control belongs to before invoking something on its UI thread.
Click to expand...

oh, I see
that's usefull to know

thanks!
 
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