Question

我正在使用以下代码创建数据应用程序 - 但是我收到了＃34;客户ID未被退回。无法创建帐户。＆＃34;不断。你知道为什么应用程序没有自动创建ID吗？

namespace SmallDataApplication27._08
{
    public partial class NewCustomer : Form
    {
        //NC-2 Storage for IDENTITY values returned from database.
        private int parsedCustomerID;
        private int orderID;

        //NC-3 Specify a connection string.
        string connstr = SmallDataApplication27._08.Utility.GetConnectionString();

        public NewCustomer()
        {
            InitializeComponent();
        }

        //NC-4 Create account.
        private void btnCreateAccount_Click(object sender, EventArgs e)
        {
            //NC-5 Set up and run stored procedure only if Customer Name is present.
            if (isCustomerName())
            {

                //NC-6 Create the connection.
                SqlConnection conn = new SqlConnection(connstr);

                //NC-7 Create a SqlCommand, and identify it as a stored procedure.
                SqlCommand cmdNewCustomer = new SqlCommand("Sales.uspNewCustomer", conn);
                cmdNewCustomer.CommandType = CommandType.StoredProcedure;

                //NC-8 Add input parameter from the stored procedure and specify what to use as its value.
                cmdNewCustomer.Parameters.Add(new SqlParameter("@CustomerName", SqlDbType.NVarChar, 40));
                cmdNewCustomer.Parameters["@CustomerName"].Value = txtCustomerName.Text;

                //NC-9 Add output parameter.
                cmdNewCustomer.Parameters.Add(new SqlParameter("@CustomerID", SqlDbType.Int));
                cmdNewCustomer.Parameters["@CustomerID"].Direction = ParameterDirection.Output;

                //NC-10 try-catch-finally
                try
                {
                    //NC-11 Open the connection.
                    conn.Open();

                    //NC-12 Run the stored procedure.
                    cmdNewCustomer.ExecuteNonQuery();

                    //NC-13 Customer ID is an IDENTITY value from the database. 
                    this.parsedCustomerID = (int)cmdNewCustomer.Parameters["@CustomerID"].Value;
                    this.txtCustomerID.Text = Convert.ToString(parsedCustomerID);

                }
                catch
                {
                    //NC-14 A simple catch.

                    MessageBox.Show("Customer ID was not returned. Account could not be created.");

实用程序文件：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;


namespace SmallDataApplication27._08
{
    internal class Utility
    {
        internal static string GetConnectionString()
        {
            //Util-2 Assume failure.
            string returnValue = null;

            //Util-3 Look for the name in the connectionStrings section.
            ConnectionStringSettings settings =
            ConfigurationManager.ConnectionStrings["SmallDataApp.Properties.Settings.connString"];

            //If found, return the connection string.
            if (settings != null)
                returnValue = settings.ConnectionString;

            return returnValue;
        }

        }
}

简单数据应用程序ADO.NET

0 个答案: