MessageBox in top other application

MessageBox in top other application for warning....

MessageBox.Show(new Form() { TopMost = true }, "You have not inputted a username or password. Would you like to configure your settings now?",
                 "Settings Needed",
                 MessageBoxButtons.YesNo,
                 MessageBoxIcon.Question);

or

MessageBox.Show(this,
                "You have not inputted a username or password. Would you like to configure your settings now?",
                "Settings Needed",
                MessageBoxButtons.YesNo,
                MessageBoxIcon.Question
                MessageBoxDefaultButton.Button1,  // specify "Yes" as the default
                (MessageBoxOptions)0x40000);      // specify MB_TOPMOST

another way using class...

static public class TopMostMessageBox
{
    static public DialogResult Show(string message)
    {
        return Show(message, string.Empty, MessageBoxButtons.OK);
    }

    static public DialogResult Show(string message, string title)
    {
        return Show(message, title, MessageBoxButtons.OK);
    }

    static public DialogResult Show(string message, string title, 
        MessageBoxButtons buttons)
    {
        // Create a host form that is a TopMost window which will be the 
        // parent of the MessageBox.
        Form topmostForm = new Form();
        // We do not want anyone to see this window so position it off the 
        // visible screen and make it as small as possible
        topmostForm.Size = new System.Drawing.Size(1, 1);
        topmostForm.StartPosition = FormStartPosition.Manual;
        System.Drawing.Rectangle rect = SystemInformation.VirtualScreen;
        topmostForm.Location = new System.Drawing.Point(rect.Bottom + 10, 
            rect.Right + 10);
        topmostForm.Show();
        // Make this form the active form and make it TopMost
        topmostForm.Focus();
        topmostForm.BringToFront();
        topmostForm.TopMost = true;
        // Finally show the MessageBox with the form just created as its owner
        DialogResult result = MessageBox.Show(topmostForm, message, title, 
            buttons);
        topmostForm.Dispose(); // clean it up all the way

        return result;
    }
} 

Called like this

TopMostMessageBox.Show(
    "This will appear in a message box that is a topmost window",
    "Title", MessageBoxButtons.AbortRetryIgnore);