Dynamic Filling of TextBox AutoComplete not working is it possible in c#?

Question

i did put this code in the “TextChanged”-event, but i think it's 'too late' there:

Private void textTiteUltTest_TextChanged(object sender, EventArgs e) {

          TextBox tb = (TextBox)sender;
          DataLayer DBClass = new DataLayer();

          try {

            string SQL = ;
            string strVar = textTiteUltTest.Text + "%";

            //Get SqlDataReader from DataClass
            SqlDataReader sqlDR = DBClass.ReturnDataReader(SQL, , strVar);
            AutoCompleteStringCollection autoCol = new AutoCompleteStringCollection();

            //fill stringcollection
            while (sqlDR.Read()) {
              autoCol.Add(sqlDR["TITE_TITLES"].ToString());
            }

            //fill autocomplete textbox
            lock (tb.AutoCompleteCustomSource.SyncRoot) {
              tb.AutoCompleteCustomSource = autoCol;
            }
          }

          catch (Exception exc) {
            Console.WriteLine(exc.Data.ToString() + exc.Message.ToString());
          }

          finally {
            //cleanup
            DBClass.Dispose();
            Console.WriteLine("'textTiteUltTest_TextChanged'");
          }

        }

        error -> AccessViolationException:
        "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
        Data: {System.Collections.ListDictionaryInternal}


        not in the try/catch-block, but here: 

            static class Program
            {
                /// <summary>
                /// The main entry point for the application.
                /// </summary>
                [STAThread]
                static void Main()
                {
                    Application.EnableVisualStyles();
                    Application.SetCompatibleTextRenderingDefault(false);
                    Application.Run(new Form1());
                }
            }

So i think, while i'm typing into the textbox the code from TextChangded-event is filling the autocomplete-stringcollection in one thread and the internal textbox-method/function needs to read from the autocomplete-stringcollection at the same time in a different thread.

The locking of SyncRoot doesn’t help at all, but I’m not even sure if I made it right in this case.

Also i have to say that this code sometimes works and sometimes it crashes. i think it depends on the speed of getting the sql server resultset.

so is this possiable ?

i am also go through this link1 and link2 but they not answer yet so please help to solve out this

The Exact Error I am getting is this: System.AccessViolationException Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Stack trace for error System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. at ICSharpCode.TextEditor.TextArea.HandleKeyPress(Char ch) at ICSharpCode.TextEditor.TextArea.SimulateKeyPress(Char ch) at ICSharpCode.TextEditor.TextArea.OnKeyPress(KeyPressEventArgs e) at System.Windows.Forms.Control.ProcessKeyEventArgs(Message& m) at System.Windows.Forms.Control.ProcessKeyMessage(Message& m) at System.Windows.Forms.Control.WmKeyChar(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.TextBoxBase.WndProc(Message& m)
   at System.Windows.Forms.RichTextBox.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Would be easier to understand if you post the exception/error message into your post — cscmh99, Sep 13 '16 at 09:17

score 0 · Answer 1 · answered Sep 28 '16 at 11:11

Bind textbox during form load instead of textchanged event.TextBox will automatically show filterd suggestion entered by user.

    List<string> s = new List<string>();
    s.Add("abc");
    s.Add("aaa");
    s.Add("acb");           

    textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
    textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
    AutoCompleteStringCollection data = new  AutoCompleteStringCollection();
    data.AddRange(s.ToArray());

    textBox1.AutoCompleteCustomSource = data;

Dynamic Filling of TextBox AutoComplete not working is it possible in c#?

1 Answers1