5

鉴于此代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
//Include mysql client namespace.

using MySql.Data.MySqlClient;   // That one doesn't work !!!
using System.Configuration;

namespace CSharpMySqlSample
{
    public partial class frmMySqlSample : Form
    {
        //Read connection string from application settings file
        string   ConnectionString = ConfigurationSettings.AppSettings["ConnectionString"];
        MySqlConnection connection;
        MySqlDataAdapter adapter;
        DataTable DTItems;
        public frmMySqlSample()
        {
            InitializeComponent();
        }

        private void frmMySqlSample_Load(object sender, EventArgs e)
        {
            //Initialize mysql connection
            connection = new MySqlConnection(ConnectionString);

            //Get all items in datatable
            DTItems = GetAllItems();

            //Fill grid with items
            dataGridView1.DataSource = DTItems;
        }

        //Get all items from database into datatable
        DataTable GetAllItems()
        {
            try
            {
                //prepare query to get all records from items table
                string query = "select * from items";
                //prepare adapter to run query
                adapter = new MySqlDataAdapter(query, connection);
                DataSet DS = new DataSet();
                //get query results in dataset
                adapter.Fill(DS);

                // Set the UPDATE command and parameters.
                adapter.UpdateCommand = new MySqlCommand(
                    "UPDATE items SET ItemName=@ItemName, Price=@Price, AvailableQuantity=@AvailableQuantity, Updated_Dt=NOW() WHERE ItemNumber=@ItemNumber;",
                    connection);
                adapter.UpdateCommand.Parameters.Add("@ItemNumber", MySqlDbType.Int16, 4, "ItemNumber");
                adapter.UpdateCommand.Parameters.Add("@ItemName", MySqlDbType.VarChar, 100, "ItemName");
                adapter.UpdateCommand.Parameters.Add("@Price", MySqlDbType.Decimal, 10, "Price");
                adapter.UpdateCommand.Parameters.Add("@AvailableQuantity", MySqlDbType.Int16, 11, "AvailableQuantity");
                adapter.UpdateCommand.UpdatedRowSource = UpdateRowSource.None;

                // Set the INSERT command and parameter.
                adapter.InsertCommand = new MySqlCommand(
                    "INSERT INTO items VALUES (@ItemNumber,@ItemName,@Price,@AvailableQuantity,NOW());",
                    connection);
                adapter.InsertCommand.Parameters.Add("@ItemNumber", MySqlDbType.Int16, 4, "ItemNumber");
                adapter.InsertCommand.Parameters.Add("@ItemName", MySqlDbType.VarChar, 100, "ItemName");
                adapter.InsertCommand.Parameters.Add("@Price", MySqlDbType.Decimal, 10, "Price");
                adapter.InsertCommand.Parameters.Add("@AvailableQuantity", MySqlDbType.Int16, 11, "AvailableQuantity");
                adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.None;

                // Set the DELETE command and parameter.
                adapter.DeleteCommand = new MySqlCommand(
                    "DELETE FROM items "
                    + "WHERE ItemNumber=@ItemNumber;", connection);
                adapter.DeleteCommand.Parameters.Add("@ItemNumber",
                  MySqlDbType.Int16, 4, "ItemNumber");
                adapter.DeleteCommand.UpdatedRowSource = UpdateRowSource.None;

                //return datatable with all records
                return DS.Tables[0];
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            return null;
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            try
            {
                //Save records in database using DTItems which is datasource for Grid
                adapter.Update(DTItems);
                //Refresh grid
                DTItems = GetAllItems();
                dataGridView1.DataSource = DTItems;
                MessageBox.Show("Items saved successfully...");
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            if (dataGridView1.SelectedRows.Count > 0)
            {
                //Delete a row from grid first.
                dataGridView1.Rows.Remove(dataGridView1.SelectedRows[0]);

                //Save records again. This will delete record from database.
                adapter.Update(DTItems);

                //Refresh grid. Get items again from database and show it in grid.
                DTItems = GetAllItems();
                dataGridView1.DataSource = DTItems;
                MessageBox.Show("Selected item deleted successfully...");
            }
            else
            {
                MessageBox.Show("You must select entire row in order to delete it.");
            }
        }
    }
}

编译后我得到:

error CS0246: The type or namespace name 'MySqlConnection' could not be found (are you missing a using directive or an assembly reference?)

但我检查了连接器: 在此处输入图像描述

它已安装..

那么怎么了?

谢谢

4

6 回答 6

17

您需要添加对的引用,MySql.Data.dll但最好dll使用NuGet将其添加为包

下面是包管理器控制台命令

PM> Install-Package MySql.Data
于 2013-11-05T10:56:54.027 回答
5

也将项目中的引用添加到MySql.Data.dll

using不提供程序集。它只允许您使用命名空间中的条目,而无需每次都指定该命名空间。

于 2013-11-05T10:57:01.713 回答
2

您必须将其添加为参考

在此处输入图像描述

于 2013-11-05T10:59:15.103 回答
1

我们将在 Connector/NET 6.5.5 和更高版本 6.6.x 中添加对 VS 2012 的支持http://forums.mysql.com/read.php?38,546265,564533#msg-564533

并给出一个测试技巧的链接

http://social.technet.microsoft.com/wiki/pt-br/contents/articles/10476.instalando-mysql-connector-no-visual-studio-2011-beta.aspx

参考这个答案

于 2013-11-05T10:58:47.657 回答
1

只是一个想法,

看起来您的项目中缺少 MySql.Data ,您可以在 web.config 中声明它

确保正确配置了 web.config。

 <assemblyIdentity name="MySql.Data" publicKeyToken="c5687fc88969c44d" culture="neutral" />
 <assemblyIdentity name="MySql.Web" publicKeyToken="c5687fc88969c44d" culture="neutral" />
于 2013-11-05T11:01:09.417 回答
0

我的解决方案:

转到项目->添加参考->扩展这里添加 MySql.Data 和

于 2014-11-21T06:53:36.800 回答