> >     I should have clairified.  There is an Invoke method on the Control
> > class (and every class that derives from it), that will call the method on
> > the appropriate thread.  You don't want to call the InvokeMember method on
> > the type.

> > --
> >                               - Nicholas Paldino [MVP]

> > > yes,but I use the invoke ,it give me another error.

> > > object [] obj = new object[] {objNode};
> > > Type t=treeView1.GetType();

>  t.InvokeMember("Add",System.Reflection.BindingFlags.Default|System.Reflectio
> > > n.BindingFlags.InvokeMethod,null,treeView1.Nodes,obj);

> > > the error :An unhandled exception of type 'System.MissingMethodException'
> > > occurred in mscorlib.dll

> > > Additional information: Attempted to access a missing member.

> > > > Welson,

> > > >     Any calls made to a class that represents a UI element should be
> >  made
> >  on
> > > > the same thread that the element was created on.  You are probably
>  getting
> > > > these errors for that reason.

> > > >     You should use the Invoke method to make the call you want from
>  another
> > > > thread.

> > > > --
> > > >                               - Nicholas Paldino [MVP]

> > > > > help me!!
> > > > > I want to add a node use the following code

> > > > > private button1_click(object sender, System.EventArgs e)
> > > > > {
> > > > >     Thread th1=new Thread(new ThreadStart(DoWith));
> > > > >     th1.Start();
> > > > > }

> > > > > private void DoWith()
> > > > > {

> > > > >     TreeNode objNode=new TreeNode("This is only a test");
> > > > >     treeView1.Nodes.Add(objNode);

> > > > > }

> > > > > its give me error;but when I add text to TextBox and add a item to
>  Combox,
> > > > > it works well.
> > > > > I want to know does there any diferrence with them.

> > > > > it's the error:

> > > > > An unhandled exception of type 'System.InvalidOperationException'
>  occurred
> > > > > in system.windows.forms.dll

> > > > > Additional information: The action being performed on this control is
>  being
> > > > > called from the wrong thread. You must marshal to the correct thread
>  using
> > > > > Control.Invoke or Control.BeginInvoke to perform this action.

> > > > > welson