C#练习DataReader（转载）

本文转自http://www.cnblogs.com/Mysterious/p/3422901.html

SQL代码：

create database ThreeDb
go
USE ThreeDb;
GO
CREATE TABLE classify   --分类表
(
    id int primary key identity(1,1),
    name nvarchar(20) not null
)

GO
CREATE TABLE product  --产品表
(
    id int primary key identity(1,1),
    name nvarchar(20) not null,
    price decimal,
    number int default 0,
    c_id int FOREIGN KEY references classify(id)    
)
GO

CREATE TABLE users
(
    id int primary key identity(1,1),
    name nvarchar(20) not null,
    pwd nvarchar(20) not null
)
GO

--添加分类测试数据
insert into classify(name) values('图书');
insert into classify(name) values('家电');
insert into classify(name) values('服饰');

--添加users的测试数据
insert into users(name,pwd) values('admin','admin');

--添加商品测试数据
insert into product(name,price,number,c_id) values('arduino基础版',168,50,1);
insert into product(name,price,number,c_id) values('arduino提高版',268,50,1);
insert into product(name,price,number,c_id) values('arduino至尊版',468,50,1);
insert into product(name,price,number,c_id) values('比基尼',68,50,3);
insert into product(name,price,number,c_id) values('虎皮裙',168,50,3);
insert into product(name,price,number,c_id) values('长靴',368,50,3);
insert into product(name,price,number,c_id) values('电冰箱',3268,50,2);
insert into product(name,price,number,c_id) values('烘干机',2268,50,2);
GO

select count(*) from users where name='admin' and pwd='admin'
go

select count(*) from users where name='xxxdadad' or 1=1 --' and pwd='admin'
go

select * from classify;
go
select * from product order by c_id;
go


--无返回值
--用途：删除一条记录
CREATE PROCEDURE UP_Product_Delete
@id int
AS
    DELETE [product] WHERE id=@id
GO
--用途：修改一条记录
CREATE PROCEDURE UP_Product_Update
@id int,
@name nvarchar(20),
@price decimal(18,0),
@number int,
@c_id int
AS
    UPDATE [product] SET
    [name]=@name,[price]=@price,[number]=@number,[c_id]=@c_id
    WHERE id=@id
GO

--有返回值
--用途：增加一条记录
CREATE PROCEDURE UP_Product_ADD
@id int output,--这是返回数据
@name nvarchar(20),
@price decimal(18,0),
@number int,
@c_id int

AS
    INSERT INTO [product]([name],[price],[number],[c_id])
    VALUES(@name,@price,@number,@c_id)
    SET @id= @@IDENTITY
GO
--用途：是否已经存在
CREATE PROCEDURE UP_Product_Exist
@id int
AS
    DECLARE @TempID int
    SELECT @TempID = count(1) FROM [product] WHERE id=@id
    IF @TempID = 0
        RETURN 0
    ELSE
        RETURN 1
GO

--返回结果集
--用途：得到实体对象的详细信息
CREATE PROCEDURE UP_Product_GetModel
@id int
AS
    SELECT id,name,price,number FROM [product] WHERE id = @id
GO

--用途：查询记录信息
CREATE PROCEDURE UP_Product_GetList
AS 
    SELECT id,name,price,number,c_id FROM [Product]
GO

--ALTER 更新
--drop 删除

winform代码

Product.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;


namespace ADO.NET.SQL
{
    public class Product
    {
        string connstr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        public Product()
        {
        
        }

        public Product(int _id,string _n,decimal _p,int _num,int _c_id)
        {
            ID = _id;
            Name = _n;
            Price = _p;
            Number = _num;
            C_id = _c_id;
        }

        public int ID
        {
            get;
            set;
        }

        public string Name
        {
            get;
            set;
        }

        public decimal Price
        {
            get;
            set;
        }

        public int Number
        {
            get;
            set;
        }

        public int C_id
        {
            get;
            set;
        }

        /// <summary>
        /// 增加一种商品
        /// </summary>
        /// <param name="_n">名字</param>
        /// <param name="_p">价格</param>
        /// <param name="_num">库存</param>
        /// <param name="_c_id">所属分类</param>
        /// <returns>true、false</returns>
        public bool Add(string _n, decimal _p, int _num, int _c_id)
        {
            //using (SqlConnection conn = new SqlConnection(connstr))
            //{
            //    string sql = "insert into product(name,price,number,c_id) values('"+_n+"',"+ _p +","+ _num +","+ _c_id + ")";
            //    SqlCommand cmd = new SqlCommand(sql, conn);

            //    conn.Open();
            //    int i = cmd.ExecuteNonQuery();
            //    if (i > 0)
            //        return true;
            //    else
            //        return false;
            //} 
            
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                string sql = "UP_Product_ADD";
                SqlCommand cmd = new SqlCommand(sql, conn);
                cmd.CommandType = CommandType.StoredProcedure;

                cmd.Parameters.AddWithValue("@name", _n);
                cmd.Parameters.AddWithValue("@price", _p);
                cmd.Parameters.AddWithValue("@number", _num);
                cmd.Parameters.AddWithValue("@c_id", _c_id);

                SqlParameter pid = new SqlParameter("@id",0);
                pid.Direction = ParameterDirection.Output;
                cmd.Parameters.Add(pid);

                conn.Open();
                int i = cmd.ExecuteNonQuery();
                //System.Windows.Forms.MessageBox.Show(cmd.Parameters["@id"].Value.ToString());
                if (i > 0)
                    return true;
                else
                    return false;
            }
        }

        public void Exists(int _id)
        {
            try
            {
                using (SqlConnection conn = new SqlConnection(connstr))
                {
                    string sql = "UP_Product_Exist";
                    SqlCommand cmd = new SqlCommand(sql, conn);
                    conn.Open();
                    cmd.CommandType = CommandType.StoredProcedure;

                    SqlParameter pid = new SqlParameter("@id", _id);
                    pid.Direction = ParameterDirection.Input;
                    cmd.Parameters.Add(pid);


                    SqlParameter rv = new SqlParameter("@returnvalue", SqlDbType.Int, 4);
                    rv.Direction = ParameterDirection.ReturnValue;
                    cmd.Parameters.Add(rv);



                    int i = cmd.ExecuteNonQuery();
                    string str1 = cmd.Parameters["@returnvalue"].Value.ToString();
                    if (str1 == "0")
                    {
                        System.Windows.Forms.MessageBox.Show("未查到相同的商品ID");
                    }
                    else
                    {
                        System.Windows.Forms.MessageBox.Show("该商品ID已经存在");
                    }
                    
                    //if (i > 0)
                    //    return true;
                    //else
                    //    return false;
                }
            }
            catch (Exception exp)
            {
                System.Windows.Forms.MessageBox.Show(exp.Message);
            }
        }

        /// <summary>
        /// 更新一种商品
        /// </summary>
        /// <param name="_id">id</param>
        /// <param name="_n">名字</param>
        /// <param name="_p">价格</param>
        /// <param name="_num">库存</param>
        /// <param name="_c_id">所属分类</param>
        /// <returns>true、false</returns>
        public bool Update(int _id, string _n, decimal _p, int _num, int _c_id)
        {
            //using (SqlConnection conn = new SqlConnection(connstr))
            //{
            //    string sql = "UPDATE product SET name='" + _n + "',price = " + _p + ",number=" + _num + ",c_id=" + _c_id + "WHERE id=" + _id;
            //    SqlCommand cmd = new SqlCommand(sql, conn);

            //    conn.Open();
            //    int i = cmd.ExecuteNonQuery();
            //    if (i > 0)
            //        return true;
            //    else
            //        return false;
            //}

            using (SqlConnection conn = new SqlConnection(connstr))
            {
                string sql = "UP_Product_Update";
                SqlCommand cmd = new SqlCommand(sql, conn);

                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@id", _id);
                cmd.Parameters.AddWithValue("@name", _n);
                cmd.Parameters.AddWithValue("@price", _p);
                cmd.Parameters.AddWithValue("@number", _num);
                cmd.Parameters.AddWithValue("@c_id", _c_id);

                conn.Open();
                int i = cmd.ExecuteNonQuery();
                if (i > 0)
                    return true;
                else
                    return false;
            }
        }

        /// <summary>
        /// 移除一个
        /// </summary>
        /// <param name="_id">id</param>
        /// <returns>true、false</returns>
        public bool Remove(int _id)
        {
            //使用SQL语句
            //using (SqlConnection conn = new SqlConnection(connstr))
            //{
            //    string sql = "delete from product WHERE id=" + _id;
            //    SqlCommand cmd = new SqlCommand(sql, conn);

            //    conn.Open();
            //    int i = cmd.ExecuteNonQuery();
            //    if (i > 0)
            //        return true;
            //    else
            //        return false;
            //}

            //使用SQL方法
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                string sql = "UP_Product_Delete";
                
                SqlCommand cmd = new SqlCommand(sql, conn);
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@id", _id);

                conn.Open();
                int i = cmd.ExecuteNonQuery();
                if (i > 0)
                    return true;
                else
                    return false;
            }
        }

        /// <summary>
        /// 获取商品列表
        /// </summary>
        /// <returns>泛型</returns>
        public Dictionary<int, Product> GetAll()
        {
            //Dictionary<int, Product> plist = new Dictionary<int, Product>();
            //using (SqlConnection conn = new SqlConnection(connstr))
            //{
            //    string sql = "select * from product";
            //    SqlCommand cmd = new SqlCommand(sql, conn);
            //    conn.Open();
            //    SqlDataReader sdr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
            //    while (sdr.Read())
            //    {
            //        Product p = new Product(
            //            Convert.ToInt32(sdr["id"]),
            //            sdr["name"].ToString(),
            //            Convert.ToDecimal(sdr["price"]),
            //            Convert.ToInt32(sdr["number"]),
            //            Convert.ToInt32(sdr["c_id"])
            //            );
            //        plist.Add(Convert.ToInt32(sdr["id"]), p);
            //    }
            //    sdr.Close();
            //}
            //return plist;

            Dictionary<int, Product> plist = new Dictionary<int, Product>();
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                string sql = "UP_Product_GetList";
                SqlCommand cmd = new SqlCommand(sql, conn);

                cmd.CommandType = CommandType.StoredProcedure;

                conn.Open();
                SqlDataReader sdr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
                while (sdr.Read())
                {
                    Product p = new Product(
                        Convert.ToInt32(sdr["id"]),
                        sdr["name"].ToString(),
                        Convert.ToDecimal(sdr["price"]),
                        Convert.ToInt32(sdr["number"]),
                        Convert.ToInt32(sdr["c_id"])
                        );
                    plist.Add(Convert.ToInt32(sdr["id"]), p);
                }
                sdr.Close();
            }
            return plist;
        }
    }
}

Classify.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;

namespace ADO.NET.SQL
{
    public class Classify
    {
        string connstr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

        public int ID
        {
            get;
            set;
        }

        public string Name
        {
            get;
            set;
        }

        /// <summary>
        /// 获取所有分类
        /// </summary>
        /// <returns>分类</returns>
        public SqlDataReader GetAll()
        {
            SqlConnection conn = new SqlConnection(connstr);
            SqlCommand cmd = new SqlCommand("select * from classify", conn);
            conn.Open();
            SqlDataReader sdr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
            //不推荐
            return sdr;
        }

        /// <summary>
        /// 通过id获取名字
        /// </summary>
        /// <param name="cid"></param>
        /// <returns></returns>
        public string GetCName(int cid)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                SqlCommand cmd = new SqlCommand("select name from classify where id=" + cid.ToString(), conn);
                conn.Open();
                string str1 = cmd.ExecuteScalar().ToString();

                return str1;
            }
        }

        /// <summary>
        /// 通过名字获取id
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        public int GetCid(string name)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                SqlCommand cmd = new SqlCommand("select id from classify where name=" + name, conn);
                conn.Open();

                return Convert.ToInt32(cmd.ExecuteScalar());
            }
        }
    }
}

Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Configuration;

namespace ADO.NET.SQL
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Bind();
        }

        private void Bind()
        {
            listView1.Items.Clear();
            Classify c = new Classify();
            Product p = new Product();

            ListViewItem lvi;
            foreach (Product pr in p.GetAll().Values)
            {
                lvi = new ListViewItem(pr.ID.ToString());
                lvi.SubItems.Add(pr.Name);
                lvi.SubItems.Add(pr.Price.ToString());
                lvi.SubItems.Add(pr.Number.ToString());
                lvi.SubItems.Add(c.GetCName(pr.C_id));

                listView1.Items.Add(lvi);
            }

            SqlDataReader sdr = c.GetAll();
            while (sdr.Read())
            {
                comboBox1.Items.Add(sdr[0] + "-->" + sdr[1]);
            }
            sdr.Close();

        }

        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (listView1.SelectedItems.Count != 0)
            {
                lbl_id.Text = listView1.SelectedItems[0].Text;
                tb_name.Text = listView1.SelectedItems[0].SubItems[1].Text;
                tb_price.Text = listView1.SelectedItems[0].SubItems[2].Text;
                tb_number.Text = listView1.SelectedItems[0].SubItems[3].Text;

                string cname = listView1.SelectedItems[0].SubItems[4].Text;

                for (int i = 0; i < comboBox1.Items.Count; i++)
                {
                    int index = comboBox1.Items[i].ToString().IndexOf("-->") + 3;//得到箭头结束的位置
                    if (comboBox1.Items[i].ToString().Substring(index) == cname)
                    {
                        comboBox1.SelectedIndex = i;
                    }
                }
            }
        }

        /// <summary>
        /// 修改
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
           
                int id = int.Parse(lbl_id.Text);

                int index = comboBox1.Text.IndexOf("-->");
                int cid = int.Parse(comboBox1.Text.Substring(0, index));

                Product p = new Product();
                if (
                    p.Update
                    (
                        id,
                        tb_name.Text,
                        decimal.Parse(tb_price.Text),
                        int.Parse(tb_number.Text),
                        cid
                    )
                  )
                {
                    Bind();
                }
                else
                {
                    MessageBox.Show("没修改成功哦！");
                }
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }

        /// <summary>
        /// 添加
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            try
            {
                Product p = new Product();

                int index = comboBox1.Text.IndexOf("-->");
                int cid = int.Parse(comboBox1.Text.Substring(0, index));

                if (
                    p.Add
                    (
                        tb_name.Text,
                        decimal.Parse(tb_price.Text),
                        int.Parse(tb_number.Text),
                        cid
                    )
                  )
                {
                    Bind();
                }
                else
                {
                    MessageBox.Show("没添加成功哦！");
                }
            }
            catch(Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }

        /// <summary>
        /// 删除商品
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                int id = int.Parse(lbl_id.Text);
                Product p = new Product();
                if (
                    p.Remove(id)
                  )
                {
                    Bind();
                }
                else
                {
                    MessageBox.Show("没删除成功哦！");
                }
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }

        private void button6_Click(object sender, EventArgs e)
        {
            try
            {
                Product p = new Product();
                p.Exists(int.Parse(tb_Exist.Text));
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }
    }
}

app.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name="constr" connectionString="server=QT-201303030913;database=ThreeDb;uid=sa;pwd=*******"/>
  </connectionStrings>
</configuration>