private void Inputtb_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.Key == Key.Enter)
     {
         if (!string.IsNullOrEmpty(inputtb.Text))
         {
             if (!string.IsNullOrWhiteSpace(inputtb.Text))
             {
                 wc.Chat(inputtb.Text);
                 inputtb.Text = "";
             }
         }
     }
 }