C#

private void cmb_1_SelectedIndexChanged(object sender, EventArgs e)
{
cmd.CommandText = "SELECT * FROM [Document_DB] WHERE [Document Category] '" + cmb_1.Text + "' ";
}

Hi guys,
 
I am trying to check for inventory quantity in database. If quatinty entered in dispatch webform is less than inventory, the dispatch should continue. else i should see error message that dispatch quantity is more than inventory and terminate the process.
 
My code below gives the following results:
When i try dispatching quantity less than inventory, the error still pops up and the program does not continue to excecute dispatch.  i do not want this. 
 
I am implementing the code from addbutton that should insert item to gridview (only if quantity is more than inventory). 
 
 
 
 
 
 
int SelectedDPItem;
int InventoryQTY;
int DinventoryQTY;

SqlConnection Connection = new SqlConnection("Data Source=localhost;Initial Catalog=warehousedb;Integrated Security=True ");
SqlDataAdapter INVadapter = new SqlDataAdapter("Select ItemID, ItemName, Quantity FROM inventory ", Connection);

SelectedDPItem = int.Parse(DropDownListItem_D.SelectedValue.ToString());
// Open Connection
Connection.Open();
SqlCommand Inventorychkcommand = new SqlCommand(("Select Quantity FROM inventory " + ("WHERE (ItemName LIKE \'"
+ (DropDownListItem_D.Text + "\')"))), Connection);
InventoryQTY = Convert.ToInt32(Inventorychkcommand.ExecuteScalar());
DinventoryQTY = Convert.ToInt32(txtQuantity_D.Text);



if (InventoryQTY < DinventoryQTY)
{

{

ClientScript.RegisterStartupScript(this.GetType(), "key", "<script>alert('sorry , Stock Balance is less than requested quantity.')</script>");
}
}


else
{

{
// procedure of inserting the record
AddNewRecordRowToGrid();

txtwaybill_D.Enabled = false;
DropDownListTransp.Enabled = false;
txtTruckNo_D.Enabled = false;
txtDrivername_D.Enabled = false;
DropDownListEmployee_D.Enabled = false;
btnNew.Enabled = false;
btnPostDispatch.Enabled = true;

DropDownListItem_D.Enabled = false;
txtDispatchDate.Enabled = false;
txtDestn.Enabled = false;
txtQuantity_D.Enabled = false;
txtDestn.Enabled = false;
}