messagebox.show c# error

Code Example 1

MessageBox.Show("your message",
    "window title", 
    MessageBoxButtons.OK, 
    MessageBoxIcon.Warning // for Warning  
    //MessageBoxIcon.Error // for Error 
    //MessageBoxIcon.Information  // for Information
    //MessageBoxIcon.Question // for Question
   );

Code Example 2

MessageBox.Show("Some text", "Some title", 
    MessageBoxButtons.OK, MessageBoxIcon.Error);