Visual Studio 2012链接SQL Server 2012（C#），实现增删改查

操作系统：Win10

环境：Visual Studio 2012、SQL Server 2012

 

一、对数据库（SQL Server 2012）的操作

创建数据库Practice

CREATE DATABASE Practice；

创建数据表Student   //包含学号，姓名，性别，年龄

 CREATE TABEL Student(

Student_No varchar(5) NOT NULL,

Student_Name varchar(8) NOT NULL,

Student_Sex varchar(2) NOT NULL,

Student_Age int

);

插入数据

    INSERT INTO Student(Student_No,Student_Name,Student_Sex,Student_Age) VALUES
    ('0001','张三','男',21),

    ('0002','李四','男',22),

    ('0003','小红','女',20);

二、对Visual Studio 2012的操作

    打开Visual Studio 2012，新建项目，选择Visual C# ，双击Windows窗体应用程序，如图

点击左侧“工具箱”，点击“所有Windows窗体”，选择相应控件进行布局，如图，分别选择Button，Label，TextBox，DataGridView

（若左侧没有工具箱，点击视图，选择工具箱即可）

 

对Form1的控件编辑属性

    双击Lable1、Lable2、Lable3、Lable4，分别修改Text值为Student_No、Student_Name、Student_Sex、Student_Age;

    双击Button1、Button2、Button3、Button4，分别修改Text值为Add、Delete、Update、Search；

    将DataGridView链接到数据

   

点击确定后，再点击下一步，直到“选择数据库对象”，勾选“表”，点击完成即可，如图为建立完成的图形界面

三、Visual Studio 2012 连接 Sql Server 2012

打开SQL Server Management Studio ，复制数据库名称

打开Visual Studio 2012，选择左侧服务器资源管理器（如果没有，点击视图找到添加即可），右击数据连接，添加连接

粘贴服务器名，选择相应数据库名，确定，即连接成功

如图即为连接成功

四、键入代码

双击"Add"，进入编辑程序界面，对“增加操作”输入以下程序

private void button1_Click(object sender, EventArgs e) //Add 增加数据
        {
            string Student_No = textBox1.Text;
            string Student_Name = textBox2.Text;
            string Student_Sex = textBox3.Text;
            string Student_Age = textBox4.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();//利用链接创建Command，执行SQL语句
            cmd.CommandText = "insert into Student values('" + Student_No + "','" + Student_Name + "','" + Student_Sex + "','" + Student_Age + "')";
            int count = cmd.ExecuteNonQuery();//将返回值赋值给count 判断执行是否成功，ExecuteNonQuery的返回值为受影响的行数
            if (count > 0)
            {
                MessageBox.Show("Success!");
            }
            else
                MessageBox.Show("Error!");
        }

双击“Delete”，对“删除操作”输入以下程序

private void button2_Click(object sender, EventArgs e)//Delete 删除数据
        {
            string Student_No = textBox1.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "delete from Student where Student_No=" + Student_No;
            int count = cmd.ExecuteNonQuery();
            if (count > 0)
                MessageBox.Show("Success!");
            else
                MessageBox.Show("Error!");

        }

双击“Update”，对“更新操作”输入以下程序

 private void button3_Click(object sender, EventArgs e)//Update 更新数据
        {
            string Student_No = textBox1.Text;
            string Student_Name = textBox2.Text;
            string Student_Sex = textBox3.Text;
            string Student_Age = textBox4.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "update Student set Student_Name='" + Student_Name + "',Student_Sex='" + Student_Sex + "',Student_Age='" + Student_Age + "' where Student_No=" + Student_No;
            int count = cmd.ExecuteNonQuery();
            if (count > 0)
                MessageBox.Show("Success!");
            else
                MessageBox.Show("Error!");
        }

双击“Search”，对“查询操作”输入以下程序

private void button4_Click(object sender, EventArgs e)
        {
            
            string Student_No = textBox1.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "SELECT Student_No,Student_Name,Student_Sex,Student_Age FROM Student WHERE Student_No='" + Student_No + "'";
            Form1 r1 = new Form1();
            DataTable count = new DataTable();//创建一个空表count
            count = r1.ExecuteQuery(cmd.CommandText);//把数据库相应查询的结果放在count
            if (count !=null)
            {
                dataGridView1.DataSource = count;   //将查询结果放入到dataGridView；
            }
            else
                MessageBox.Show("This student is not exists！");
        }

并在类 Form1中新建

public DataTable ExecuteQuery(string sqlStr)     
        {
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();//打开数据库连接
            SqlCommand cmd = new SqlCommand();//对数据库执行SQL语句或存储
            cmd.Connection = con;//把con对象的引用赋值，即用SqlCommand的对象链接数据库
            cmd.CommandType = CommandType.Text;//用于指定执行动作的形式，.Text表示SqlCommand的对象CommandType的执行形式为Text
            cmd.CommandText = sqlStr;
            DataTable dt = new DataTable();
            SqlDataAdapter msda;
            msda = new SqlDataAdapter(cmd);
            msda.Fill(dt);
            con.Close();
            return dt;
        }

并且手动导入命名空间

using System.Data.SqlClient;

需要注意，SqlConnection con = new SqlConnection（“”）中对数据库的链接需要手动添加，其方法为，打开“服务器资源管理器”，选择当前数据连接，复制连接字符串中的文本即可，如图

完整代码如下

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


namespace WindowsFormsApplication5
{
    public partial class Form1 : Form
    {
        public DataTable ExecuteQuery(string sqlStr)      
        {
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();//打开数据库连接
            SqlCommand cmd = new SqlCommand();//对数据库执行SQL语句或存储
            cmd.Connection = con;//把con对象的引用赋值，即用SqlCommand的对象链接数据库
            cmd.CommandType = CommandType.Text;//用于指定执行动作的形式，.Text表示SqlCommand的对象CommandType的执行形式为Text
            cmd.CommandText = sqlStr;
            DataTable dt = new DataTable();
            SqlDataAdapter msda;
            msda = new SqlDataAdapter(cmd);
            msda.Fill(dt);
            con.Close();
            return dt;
        }
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // TODO: 这行代码将数据加载到表“practiceDataSet.Student”中。您可以根据需要移动或删除它。
            this.studentTableAdapter.Fill(this.practiceDataSet.Student);

        }

        private void button1_Click(object sender, EventArgs e)
        {
            string Student_No = textBox1.Text;
            string Student_Name = textBox2.Text;
            string Student_Sex = textBox3.Text;
            string Student_Age = textBox4.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();//利用链接创建Command，执行SQL语句
            cmd.CommandText = "insert into Student values('" + Student_No + "','" + Student_Name + "','" + Student_Sex + "','" + Student_Age + "')";
            int count = cmd.ExecuteNonQuery();//将返回值赋值给count 判断执行是否成功，ExecuteNonQuery的返回值为受影响的行数
            if (count > 0)
            {
                MessageBox.Show("Success!");
            }
            else
                MessageBox.Show("Error!");
        }

        private void button2_Click(object sender, EventArgs e)
        {
            string Student_No = textBox1.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "delete from Student where Student_No=" + Student_No;
            int count = cmd.ExecuteNonQuery();
            if (count > 0)
                MessageBox.Show("Success!");
            else
                MessageBox.Show("Error!");
        }

        private void button3_Click(object sender, EventArgs e)
        {
            string Student_No = textBox1.Text;
            string Student_Name = textBox2.Text;
            string Student_Sex = textBox3.Text;
            string Student_Age = textBox4.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "update Student set Student_Name='" + Student_Name + "',Student_Sex='" + Student_Sex + "',Student_Age='" + Student_Age + "' where Student_No=" + Student_No;
            int count = cmd.ExecuteNonQuery();
            if (count > 0)
                MessageBox.Show("Success!");
            else
                MessageBox.Show("Error!");
        }

        private void button4_Click(object sender, EventArgs e)
        {
            
            string Student_No = textBox1.Text;
            SqlConnection con = new SqlConnection("Data Source=USER-20190503GJ;Initial Catalog=Practice;Integrated Security=True");
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "SELECT Student_No,Student_Name,Student_Sex,Student_Age FROM Student WHERE Student_No='" + Student_No + "'";
            Form1 r1 = new Form1();
            DataTable count = new DataTable();//创建一个空表count
            count = r1.ExecuteQuery(cmd.CommandText);//把数据库相应查询的结果放在count
            if (count !=null)
            {
                dataGridView1.DataSource = count;   //将查询结果放入到dataGridView；
            }
            else
                MessageBox.Show("This student is not exists！");
        }
    }
}

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