The calling thread cannot access this object because a different thread owns it error pops up ?

Question

Here is my method which is showing the error.If i am not using the thread it will works fine, how to use it with the help of threading.

public void Mthread()
        {
            string s;            
            SpeechSynthesizer ss = new SpeechSynthesizer();
            s = textBox1.Text;   //Here it is showing the error.
            ss.Speak(s);
           
        }

private void button2_Click(object sender, RoutedEventArgs e)
        {
            Thread th = new Thread(Mthread);
            th.Start();
            
        }

---

MSDN Forum

Answer 1

Hi,

This is because UI thread owned the textBox1, we can't use it directly in another thread. You can adjust the following code to fit your requirement:

public void Mthread()
        {
            string s;           
            SpeechSynthesizer ss = new SpeechSynthesizer();
            textBox1.Dispatcher.Invoke(DispatcherPriority.Normal,
                (SendOrPostCallback)delegate
                {                                      
                    s = textBox1.Text;                   
                },
                null);           

             ss.Speak(s);           
        }

Thanks.

---

Leo Tang [MSFT]
MSDN Community Support | Feedback to us
Get or Request Code Sample from Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 2

Hello LeoTang

It works ,  Thanks a lot

But i think we have  to declare the string s to global , why we have to declare it as globlal ?

---