Exception Log :  'DepartmentDropDownList' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value

Stack trace

 at System.Web.UI.WebControls.ListControl.set_SelectedValue(String value) at Pages_FrontOffice_AppointmentScheduling_PatientRegister.AssignValuesToControls(Int64 Id) at Pages_FrontOffice_AppointmentScheduling_PatientRegister.LinkButton_Click(Object sender, EventArgs e)