c# multithreading

I need a safe way to pass information from a thread to the main thread in which my UI was created in. I need a textbox to receive information and display it while on a different thread.

Code:

//I added a public delegate to the main form class
public delegate void UpdateTextCallback(string message);

//then an invoke function
        public void InvokeUI(string linetoadd)
        {
            txtServerStatus.BeginInvoke(new UpdateTextCallback(AddToText));
            
        }

I just get a InvalidOperationException was unhandled error

I read the help and it says its a warning because its unsafe to access a UI element from a different thread then what it was created on so is there a way to pass the string to the main ui thread and have it invoke the textbox, instead of having the other thread invoke it.

 

I don't do C#, but I found these links on Google:
http://codeidol.com/csharp/essential-csharp/Multithreading/Synchronization/ shows how to use synchronization, and includes something about user interface stuff.
http://blogs.microsoft.co.il/blogs/tomershamam/archive/2007/09.aspx talks about threads accessing UI elements in other threads under the heading WPF Model Data Binding - Part II and shows a workaround.