title: C#: string.Trim() not removing white spaces
body: <p>I have a prompt asking user to enter a date (in a specific format).  Then I trim the string, however if the there was an extra space when I hit 'Enter' in the prompt box, the string still comes out with an extra space after the trim.  I'll post my prompt box code too.  My string is: Jul 29, 2015 1:32:01 PM PDT  and Jul 30, 2015 12:34:27 PM PDT</p>
  
  <pre><code>    string afterpromptvalue = Prompt.ShowDialog("Enter earliest Date and Time", "Unshipped Orders");
                      afterpromptvalue.Trim();
                      string beforepromptvalue = Prompt.ShowDialog("Enter latest Date and Time", "Unshipped Orders");
                      beforepromptvalue.Trim();
  
   string format = "MMM dd, yyyy h:mm:ss tt PDT";
  
              CultureInfo provider = CultureInfo.InvariantCulture;
  
              afterpromptvalue.Trim();
              beforepromptvalue.Trim();
  
  
              DateTime createdAfter = DateTime.ParseExact(afterpromptvalue, format, provider);
  
  
  
              DateTime createdBefore = DateTime.ParseExact(beforepromptvalue, format, provider);
  
  public static class Prompt
  {
      public static string ShowDialog(string text, string caption)
      {
          Form prompt = new Form();
          prompt.Width = 500;
          prompt.Height = 150;
          prompt.FormBorderStyle = FormBorderStyle.FixedDialog;
          prompt.Text = caption;
          prompt.StartPosition = FormStartPosition.CenterScreen;
          Label textLabel = new Label() { Left = 50, Top=20, Text=text };
          TextBox textBox = new TextBox() { Left = 50, Top=50, Width=400 };
          Button confirmation = new Button() { Text = "Ok", Left=350, Width=100, Top=70, DialogResult = DialogResult.OK };
          confirmation.Click += (sender, e) =&gt; { prompt.Close(); };
          prompt.Controls.Add(textBox);
          prompt.Controls.Add(confirmation);
          prompt.Controls.Add(textLabel);
          prompt.AcceptButton = confirmation;
  
          return prompt.ShowDialog() == DialogResult.OK ? textBox.Text : "";
      }
  }
  </code></pre>