title: I have to get a message if textbox has null value for double value
body: <p>I have to get a message if a textbox has null value for double value, i tried the below code, but got an error on the 2nd condition, please help!</p>
  
  <pre><code>acno = Txtacc.Text;
  recoverymoney = double.Parse(Txtamount.Text);
  
  if (string.IsNullOrEmpty(this.Txtacc.Text))
  {
      MessageBox.Show("You have not entered account number, Please Enter it...!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
  }
  else if (string.IsNullOrEmpty(this.Txtamount.Text))
  {
      MessageBox.Show("You have not entered amount, Please Enter it..!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
  }
  </code></pre>