C#•2y ago

❔ c# wpf textbox access violation

Hello does anyone know how can i edit the TextBox1.Text within the Task.run so i don't have an access violation ? here is the code :

private async void Button_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                Socket Server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                Server.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 80));
                Server.Listen(2);

                Socket Client;

                await Task.Run(() =>
                {
                    Client = Server.Accept();
                    TextBox1.Text = "Hello";
                    
                });
            }

            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex);
            }
        }

private async void Button_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                Socket Server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                Server.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 80));
                Server.Listen(2);

                Socket Client;

                await Task.Run(() =>
                {
                    Client = Server.Accept();
                    TextBox1.Text = "Hello";
                    
                });
            }

            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex);
            }
        }

3 Replies

reflectronic•2y ago

you can only edit the control on the UI thread, the Task.Run takes you to a different thread so it won't work. you can "come back" to the UI thread temporarily with Dispatcher.Invoke

await Task.Run(() => 
{
    Client = Server.Accept();
    Dispatcher.Invoke(() => 
    {
        TextBox1.Text = "Hello"; 
    }
}

await Task.Run(() => 
{
    Client = Server.Accept();
    Dispatcher.Invoke(() => 
    {
        TextBox1.Text = "Hello"; 
    }
}

(though, if i may, i would suggest:)

await Task.Run(async () => 
{
    Client = await Server.AcceptAsync();
    Dispatcher.Invoke(() => 
    {
        TextBox1.Text = "Hello"; 
    }
}

await Task.Run(async () => 
{
    Client = await Server.AcceptAsync();
    Dispatcher.Invoke(() => 
    {
        TextBox1.Text = "Hello"; 
    }
}

MotherBrokerOP•2y ago

Thanks it worked

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ c# wpf textbox access violation