'Service1.InsertSupplier（Supplier）'：并非所有代码路径都返回一个值

Question

public int InsertSupplier(Supplier supplier)
{
    try
    {
        comm.CommandText = "INSERT INTO SupplierTable(@sup_id, @Supplier_Name, @Address, @City, @Phone, @Email, @TIN)";
        comm.Parameters.AddWithValue("sup_id", supplier.id);
        comm.Parameters.AddWithValue("Supplier_Name", supplier.NameSupplier);
        comm.Parameters.AddWithValue("Address", supplier.Address);
        comm.Parameters.AddWithValue("City", supplier.City);
        comm.Parameters.AddWithValue("Phone", supplier.Phone);
        comm.Parameters.AddWithValue("Email", supplier.Email);
        comm.Parameters.AddWithValue("TIN", supplier.TIN);

        comm.CommandType = CommandType.Text;
        conn.Open();

        return comm.ExecuteNonQuery();


    }
    catch (Exception)
    {

    }

    finally
    {
        if (conn != null)
        {
            conn.Close();
        }
    }

}

Answer 1

万一发生异常，您的方法将返回return。

在末尾添加类似return -1;的内容：

public int InsertSupplier(Supplier supplier)
{
    try
    {
        // your code here
    }
    catch (Exception)
    {

    }    
    finally
    {
        if (conn != null)
        {
            conn.Close();
        }
    }

    return -1; // or change this to more proper value
}