Select Date from Database:
First check the current date format like below:
lblMsg.Text = CultureInfo.CurrentCulture.DateTimeFormat.ShortDatePattern;
if (lblMsg.Text == "dd/MM/yyyy")
txtd.Text = DateTime.Parse(dr["EventDate"].ToString()).ToString("dd/MM/yyyy");
else
txtd.Text = DateTime.Parse(dr["EventDate"].ToString()).ToString("MM/dd/yyyy");
Add or Update: Similarly you can check either the current date format is dd/MM/yyyy OR "MM/dd/yyyy"
if (lblMsg.Text == "dd/MM/yyyy")
usinfo.BDate = DateTime.ParseExact(txtDOB.Text.ToString(), "dd/MM/yyyy", CultureInfo.InvariantCulture);
else
usinfo.BDate = DateTime.ParseExact(txtDOB.Text.ToString(), "MM/dd/yyyy", CultureInfo.InvariantCulture);
lblMsg.Text = "";