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I have a windows application in which I am using a web reference to show the current SMS balance in the account of a particular user.Here is the code that I am using:

Thread t1 = new Thread(new ThreadStart(ShowWaitMessage));
            t1.Start();
            XmlNode xmlnde = ws.BSAcBalance(txtLoginId.Text, txtPassword.Text);
            string sResponse = xmlnde.ChildNodes[0].InnerXml;
            if (sResponse.Contains("Authentication Failed"))
            {
                t1.Abort();
                MessageBox.Show("Invalid login id or password !", "Information", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);                    
            }
            else
            {
                t1.Abort();
                MessageBox.Show("Total balance in your account is Rs : " + sResponse , "Information", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            }

public void ShowWaitMessage()
    {             
        MessageBox.Show("Please Wait ......");
    }

The ws.BSAcBalance is the method that connects the application to the web, it takes some 2 to 3 seconds to execute. In the meanwhile, I want to display a "Please Wait" message for which I am trying to use threading and displaying the message through a message box.Now once the desired operation is completed, I want the "Please Wait" message box to hide, but that doesn't happen.What should I do ?

TVicky
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    Please wait shouldn't be a message box at all. It should be something like splash screen or a non modal window. It it were a simple form you could close it using `form.Close()` Also `Thread.Abort` should never be used. – Sriram Sakthivel Dec 06 '14 at 12:40
  • Get your UI out the thread. Show the message, make the call in another thread, when it returns have it call back to the UI with the value. In the callback function show the value and hide the box. – dbugger Dec 06 '14 at 12:44
  • Is it maybe sufficient to just change the mouse cursor to the wait cursor? – RenniePet Dec 06 '14 at 13:24
  • Yes @RenniePet , even that would do. – TVicky Dec 06 '14 at 13:28
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    OK, http://stackoverflow.com/questions/1568557/how-can-i-make-the-cursor-turn-to-the-wait-cursor But you must avoid getting multi-threading involved in the UI, even changing the cursor. – RenniePet Dec 06 '14 at 13:32
  • This works @RenniePet , it is not exactly what I was looking for but this is good enough for me. – TVicky Dec 06 '14 at 13:40

1 Answers1

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MessageBox is designed to take user's input. So it does NOT present any "native" means to close it programmatically. You have 2 options:

Option 1.

a) Define a new class WaitForm, derived from System.Windows.Forms.Form;

b) Define public method CloseMe in WaitForm that would execute Form.Close() once being called from outside.

c) Create an instance of WaitForm when you need to display the wait message and call its inherited method ShowDialog().

d) Once your operation is completed, call CloseMe from you thread.

Option 2:(force MessageBox closing)

Use Windows API function FindWindow, which is not native for .NET. So you will have to include:

[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);
  • and then, once the operation is done, call

IntPtr hWnd = FindWindowByCaption(IntPtr.Zero, <YourWaitMessageBoxTitle>); if (hWnd.ToInt32() != 0) PostMessage(hWnd, WM_CLOSE, 0, 0);

Arkady Yampolsky
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