how to set datetimepicker with null value if date not selected(c# winforms)

Question

Binding b = new Binding( \"Value\", person, \"BdayNullable\", true );
dtBirthdayNullable.DataBindings.Add( b );
b.Format += new ConvertEventHandler( dtBirthdayNullab         


        

Answer 1

this is how i solved it. I couldn't have NULLS so I defined 1/1/1980 12am as MYNULLDATE. I used databinding on the text and value of the datetimepicker. I did not use the checkbox in the datetimepicker. I did not alternat formats from short to custom. It appeared to fire valuechanged events so i just used custom and changed the customformat. I used a flowpanel and a NONBOUND checkbox to sit in front of the datetimepicker.

Sample of the code

   private void dateTimePicker_ValueChanged(object sender, EventArgs e)
    {
        if (sender != null && sender.GetType() == typeof(DateTimePicker))
        {
            if (((DateTimePicker)(sender)).Value == MYNULLDATE)
            {
                ((DateTimePicker)(sender)).CustomFormat = " ";
                checkBoxDate.Checked = false;
            }
            else
            {
                ((DateTimePicker)(sender)).CustomFormat = "M/d/yyyy";
                checkBoxDate.Checked = true;
            }
        }

    }

In the Non Bound CheckBox

  private void checkBoxDate_Click(object sender, EventArgs e)
    {
        if (bindingSource != null && bindingSource.Current != null &&
             bindingSource.Current.GetType() == typeof(MyRecord))
        {
            MyRecord a = (MyRecord)bindingSource.Current;
            if (checkBoxDate.Checked == false)
            {
                a.Date = MYNULLDATE;
                dateTimePicker.Enabled = false;
            }
            else
            {
                if (a.Date == null || a.Date == MYNULLDATE)
                {
                    dateTimePicker.Enabled = true;
                    a.Date = DateTime.Now;
                }
            }
            bindingSource.ResetBindings(false);
        }
    }