Error Creating Window Handle in C#

Question

I have been working on tabcontrol in C#. Where i have added textboxes, labels,datagridviews, panels in all 10 tabs. When i am trying to use autocomplete in textbox it gives me an exception stating "Error Creating Window Handle-Win32 Exception". Below is my code:

    private void textBoxCustomerMNO_Enter(object sender, EventArgs e)
    {

        textBoxCustomerMNO.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
        textBoxCustomerMNO.AutoCompleteSource = AutoCompleteSource.CustomSource;
        AutoCompleteStringCollection CustomerMobileNo = new AutoCompleteStringCollection();

        string Query = "select PATIENT_MNO from MEDICINES_SALE_RECEPIT";
        DataTable CustomerNos = clsConnection.GetDataTable(Query);
        if (CustomerNos.Rows.Count > 0)
        {
            foreach(DataRow row in CustomerNos.Rows)
            {
                CustomerMobileNo.Add(row["PATIENT_MNO"].ToString().Trim());
            }
        }

    }

1. connection class is already created.

textBoxCustomerMNO.AutoCompleteMode = AutoCompleteMode.SuggestAppend; — user3032171, Nov 25 '13 at 12:01
Exception thrown very first time this code executes or what..? — Sriram Sakthivel, Nov 25 '13 at 12:03
on Form load the focus in on CustomerMNO textbox (being in Enter event) and so it gives an exception at the very beginning — user3032171, Nov 25 '13 at 12:04
FYI - the Enter event wouldn't really be the way to go to do a SQL query. — Ahmed ilyas, Nov 25 '13 at 12:58
Here's some general help on Windows Handle creation issues: http://stackoverflow.com/a/222843/2258 I guess before I would start blaming .AutoCompleteMode, I would make sure I was not falling into these traps. — Richard Morgan, Nov 25 '13 at 13:08
there is no problem with SQL queries. My entire project works perfectly fine this way. I only have problem with the mentioned textbox — user3032171, Nov 25 '13 at 13:12

score 0 · Answer 1 · answered Dec 19 '13 at 19:14

i had a similar problem when i was going to set AutoCompleteMode property of a textbox in GotFocus event. this behaviour is strange but you can resolve it easily by setting AutoCompleteMode property before Enter event or GotFocus event for example in Form_Load event or through the properties window in design mode (of course if your textbox is created & exists in design mode).

//put this in your **Form-Load** event:
textBoxCustomerMNO.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
//.. and remove it from the textBoxCustomerMNO_Enter event!

if you create textBoxCustomerMNO textbox dynamically, then set AutoCompleteMode property also there and before defining the Enter even:

t = new TextBox();
t.AutoCompleteMode = AutoCompleteMode.SuggestAppend; //set this before Enter event! 
t.Enter += new EventHandler(...)

score 0 · Answer 2 · answered Feb 17 '14 at 11:31

if it greater than 0, Releases all resources used by the Component

        if (this.Handle.ToInt32() > 0)
            {

                if (components != null)
                {
                    components.Dispose();
                }
             }

Error Creating Window Handle in C#

2 Answers2