private void EmailAddresstextBox_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.KeyCode == Keys.Enter)
     {
         WebServiceUrltextBox.Focus();
         e.Handled = true;
     }
 }
        private void WebServiceUrltextBox_Leave(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(WebServiceUrltextBox.Text))
            {
                string urlAddress = WebServiceUrltextBox.Text.Trim();
                Regex  mRegxExpression;
                Regex  mRegxExpression1;

                mRegxExpression  = new Regex(@"^(ht|f)tp(s?)\:\/\/[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*(:(0-9)*)*(\/?)([a-zA-Z0-9\-\.\?\,\'\/\\\+&%\$#_]*)?$");
                mRegxExpression1 = new Regex(@"^(www.)[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*(:(0-9)*)*(\/?)([a-zA-Z0-9\-\.\?\,\'\/\\\+&%\$#_]*)?$");

                if ((!mRegxExpression.IsMatch(urlAddress)) && (!mRegxExpression1.IsMatch(urlAddress)))
                {
                    MessageBox.Show("Please type your valid Url Address.", "MojoCRM", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    WebServiceUrltextBox.Clear();
                    WebServiceUrltextBox.Focus();
                }
            }
        }