I need to autofill the textbox based on dropdownlist selection I have fields in Table m_VendorType VendorTypeID, VendorTypeName,VendorTypeFee I have one dropdownlist with DataTextField="VendorTypeName" DataValueField="VendorTypeID" Now I want to have vendor Fee autofilled on the textbox below, how to do that? Here is my code, but its not working: <ControlDataSource Id="dsVendorType" CommandText="S