Hi,
if Your date Format is dd/MM/yyyy then u need to convert it in sql Format
using following Code
IFormatProvider provider = new System.Globalization.CultureInfo("en-CA", true);
string strDate = DateTime.Parse(txtDate.Text.Trim(), provider, System.Globalization.DateTimeStyles.NoCurrentDateDefault).Date.ToString();
then u can pass it to Db ok
Best Luck