As suggested by jbutler483
I tried to do but I couldn't get any solution finally as my own knowledge I used following code
private void dtpdob_ValueChanged(object sender, EventArgs e)
{
int year = DateTime.Today.Year - dtpdob.Value.Year;
int month = DateTime.Today.Month - dtpdob.Value.Month;
int day = DateTime.Today.Day - dtpdob.Value.Day;
var a = year.ToString();
var b = month.ToString();
var c = day.ToString();
if (day != 0 && month!=0 && year!=0)
{
if(day!=1)
txtage.Text = a + " Years " + b + " Months " + c + " Days ";
else
txtage.Text = a + " Years " + b + " Months " + c + " Day ";
}
else if (day == 0 && month == 0)
txtage.Text = a + " Years ";
else if (day == 0 && month != 0)
txtage.Text = a + " Years " + b + " Months ";
else
txtage.Text = a + " Years " + b + " Months " + c + " Days ";
}