title: Type in the textbox with LETTERS only and also with only one Minus sign(-) only Preferably using the ASCII code
body: <p>I want to use the <strong><em>ASCII code</em></strong> of <strong><em>minus sign</em></strong>. Is there possible way on doing it? Use minus sign <strong><em>only once</em></strong>.
  <strong><em>45</em></strong> is the ASCII code of minus sign(-)</p>
  
  <pre><code>private void txtcity_KeyPress(object sender, KeyPressEventArgs e)
  {
      e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back);// e.KeyChar == (char)Keys.45);
  }
  </code></pre>