Form not loading correctly

Question

I'm trying to build a TAPI based phone call system using JulMar's Atapi x86. One of the functions is to pop a specific form on an inbound call. However, whenever the form pops, it comes up incorrect, as shown below (I have tried several forms as a test and they all do the same thing). There is no error, nothing in the output window to suggest what the issue is.

Code:

private void incomingcall(object sender, NewCallEventArgs e)
    {
        string phonenumber = e.Call.CallerId; //get the phone number of the call
        SqlCommand getincoming = new SqlCommand(Querystrings.getincomingquery(), DB);
        getincoming.Parameters.AddWithValue("@@TELEPHONE", phonenumber);
        DataTable results = new DataTable(); 
        try
        {
            DB.Open();
            using (var results = getincoming.ExecuteReader())
            {
                results.Load(results);
            }
        }
        catch (Exception ex)
        {
            Inbound ib = new Inbound(phonenumber, null);
            ib.Show();
        }
        finally
        {
            DB.Close();
        }
        if (results.Rows.Count == 1)
        {
            loadcontactrequest(Convert.ToInt32(results.Rows[0].ItemArray[0]), phonenumber);
        }
        else
        {
            loadinbound(phonenumber, results);
        }
    }

I have loaded these forms outside of this function at other points, meaning it is something to do with this function. Does anybody know where I'm going wrong?

EDIT:

private void loadcontactrequest(int ContactID, string phonenumber)
    {
        ContactRequest cr = new ContactRequest(ContactID, Global.loginbound("Single customer found", phonenumber));
        cr.Show();
    }

These functions have been tested elsewhere and work correctly individually, I believe it might be TAPI related.

EDIT 2 - Delegate:

public static void inittapi()
    {
        if (TestOptions.notapi)
            return;
        tapi = new TapiManager("Omitted");
        tapi.Initialize();
        foreach (TapiLine ad in tapi.Lines) //Get all lines available to this PC
        {
            if (ad.Name.ToUpper().Contains("Omitted")) 
            {
                phoneline = ad;
                phoneline.Open(MediaModes.All); //Open the phone line for making and receiving calls
                phoneline.NewCall += new EventHandler<NewCallEventArgs>(new TAPI().incomingcall); //Add the incoming call event handler
            }
        }
    }

I assume `loadcontactrequest()` is opening the form? If so, the problem is likely in there. Show that code. — DonBoitnott, May 16 '16 at 11:21
GUIs have to be run from the main thread. Is your TAPI call back (or whatever) happening in the main thread? — AnthonyLambert, May 16 '16 at 11:28
I add a delegate for the call handle inside the main thread (1 of the first things done before the pop of the main form). As stated above, while debugging, nothing happens except that form appears like that. No errors, no messages, nothing in the output window. — Ryan Hargreaves, May 16 '16 at 11:30

NineBerry · Accepted Answer · 2016-05-16T11:46:32.323

2

It's possible that this event is triggered on a different thread than the UI thread of your application.

Modify the method like this to test whether this is the problem:

private void incomingcall(object sender, NewCallEventArgs e)
{
     Form form;

     if(Application.OpenForms.Count > 0)
     {
          form = Application.OpenForms[0];
     }

     if (form != null && form.InvokeRequired)
     {
          form.BeginInvoke(new Action(() => { incomingcall(sender, e); }));
          return;
     }

     // Your current code goes here
}

This will identify that we are in a different thread than your main form (form) was created on and then execute the function again on the main form's thread.

edited May 16 '16 at 11:46

answered May 16 '16 at 11:31

NineBerry

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The code is in a separate class. That code is throwing a compile-time error: 'TAPI' does not contain a definition for 'InvokeRequired' and no extension method 'InvokeRequired' accepting a first argument of type 'TAPI' could be found (are you missing a using directive or an assembly reference?) – Ryan Hargreaves May 16 '16 at 11:33
Does the class have some reference to the main form or some other open form availble? Then use that instead of this. Or use Application.OpenForms[0] – NineBerry May 16 '16 at 11:36
Lovely, that has fixed the issue. I didn't realise UI had to be called from the main thread. Thanks :) – Ryan Hargreaves May 16 '16 at 11:39
One can have multiple threads with UI in a winforms application, but these other threads need to include their own message loop for the UI to work correctly. – NineBerry May 16 '16 at 11:44

Form not loading correctly

1 Answers1