Question

Could someone demonstrate how you could implement DateTime.TryParse into my current code which takes in intergers. For example a 24 hour time format 23:00

private void textBox2_Validating(object sender, CancelEventArgs e)
{
    int numberEntered;

    if (int.TryParse(textBox2.Text, out numberEntered))
    {
         if (numberEntered < 1 || numberEntered > 28)
         {
              MessageBox.Show("");
              textBox2.Text = 5.ToString();
         }
    }
    else
    {
         MessageBox.Show("");
         textBox2.Text = 5.ToString();
    }
}

Answer 1

This should do what you want:

    void textBox1_Validating(object sender, CancelEventArgs e)
    {
        DateTime dateEntered;

        if (DateTime.TryParseExact(textBox1.Text, "HH:mm", System.Globalization.CultureInfo.CurrentCulture, System.Globalization.DateTimeStyles.None, out dateEntered))
        {
            MessageBox.Show(dateEntered.ToString());
        }
        else
        {
            MessageBox.Show("You need to enter valid 24hr time");
        }

    }

I would recommend doing some reading up on the various parameters available for DateTime.TryParseExact, and choosing the ones that match your situation with care. Also have a look at the values of actual DataTime objects that get generated by this parse, since they will have a Date part as well – if you use this data later on (particularly for comparing these times) these details could prove important.