System.NullReferenceException: Object reference not set to an instance of an object.

See more:

C#

I have a problem in my app development. can anyone help please.

Source Error:


Line 34: String Payrollnumber =
Line 35: DataList1.DataKeys[e.Item.ItemIndex].ToString();
Line 36: String FirstName =
Line 37: ((TextBox)e.Item.FindControl("FirstName")).Text;
Line 38: String MiddleName =

source Code

protected void DataList1_UpdateCommand(object source,
       DataListCommandEventArgs e)
   {
       String Payrollnumber =
            DataList1.DataKeys[e.Item.ItemIndex].ToString();
       String FirstName =
            ((TextBox)e.Item.FindControl("FirstName")).Text;
       String MiddleName =
            ((TextBox)e.Item.FindControl("MiddleName")).Text;
       String LastName =
            ((TextBox)e.Item.FindControl("LastName")).Text;
       String Designation =
            ((TextBox)e.Item.FindControl("Designation")).Text;
       SqlDataSource1.UpdateParameters["PayrollNumber"].DefaultValue
           = Payrollnumber;
       SqlDataSource1.UpdateParameters["FirstName"].DefaultValue
           = FirstName;
       SqlDataSource1.UpdateParameters["MiddleName"].DefaultValue
           = MiddleName;
       SqlDataSource1.UpdateParameters["LastName"].DefaultValue
           = LastName;
       SqlDataSource1.UpdateParameters["Designation"].DefaultValue
           = Designation;
       SqlDataSource1.Update();

       DataList1.EditItemIndex = -1;
       DataList1.DataBind();
   }