以users表為例，有三個字段，自增長的編號id，int類型；名稱name，nvarchar類型，密碼pwd，nvarchar類型
首先在vs2005中引入using System.Data.SqlClient;命名空間
??????? /// <summary>
??????? /// 增加
??????? /// </summary>
??????? /// <param name="name">姓名</param>
??????? /// <param name="pwd">密碼</param>
??????? /// <returns></returns>
??????? public int Insert(string name,string pwd)
??????? {
??????????? SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Test;Integrated Security=True");//Initial Catalog后面跟你數據庫的名字,如果你的SqlServer服務器名稱后面不帶SQLEXPRESS，那么Data Source=.
??????????? conn.Open();???????????
??????????? string sql = "insert into users(name,pwd) values(@name,@pwd)";
??????????? SqlCommand cmd = new SqlCommand(sql,conn);
??????????? SqlParameter parn = new SqlParameter("@name",name);
??????????? cmd.Parameters.Add(parn);
??????????? SqlParameter parp = new SqlParameter("@pwd", pwd);
??????????? cmd.Parameters.Add(parn);
??????????? int result = cmd.ExecuteNonQuery();//result接收受影響行數，也就是說result大于0的話表示添加成功
??????????? conn.Close();
??????????? cmd.Dispose();
??????????? return result;
??????? }

??????? /// <summary>
??????? /// 刪除
??????? /// </summary>
??????? /// <param name="name">姓名</param>
??????? /// <param name="pwd">密碼</param>
??????? /// <returns></returns>
??????? public int Update(int id)
??????? {
??????????? SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Test;Integrated Security=True");//Initial Catalog后面跟你數據庫的名字,如果你的SqlServer服務器名稱后面不帶SQLEXPRESS，那么Data Source=.
??????????? conn.Open();
??????????? string sql = "delete from users where id=@id";
??????????? SqlCommand cmd = new SqlCommand(sql, conn);
??????????? SqlParameter parn = new SqlParameter("@id", id);
??????????? cmd.Parameters.Add(parn);???????
??????????? int result = cmd.ExecuteNonQuery();//result接收受影響行數，也就是說result大于0的話表示刪除成功
??????????? conn.Close();
??????????? cmd.Dispose();
??????????? return result;

??????? }

??????? /// <summary>
??????? /// 修改
??????? /// </summary>
??????? /// <param name="name">姓名</param>
??????? /// <param name="pwd">密碼</param>
??????? /// <returns></returns>
??????? public int Insert(string name, string pwd,int id)
??????? {
??????????? SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Test;Integrated Security=True");//Initial Catalog后面跟你數據庫的名字,如果你的SqlServer服務器名稱后面不帶SQLEXPRESS，那么Data Source=.
??????????? conn.Open();???????????
??????????? string sql = "update users set name=@name,pwd=@pwd where id=@id";
??????????? SqlCommand cmd = new SqlCommand(sql, conn);
??????????? SqlParameter parn = new SqlParameter("@name", name);
??????????? cmd.Parameters.Add(parn);
??????????? SqlParameter parp = new SqlParameter("@pwd", pwd);
??????????? cmd.Parameters.Add(parn);
??????????? SqlParameter pari = new SqlParameter("@id", id);
??????????? cmd.Parameters.Add(pari);
??????????? int result = cmd.ExecuteNonQuery();//result接收受影響行數，也就是說result大于0的話表示修改成功
??????????? conn.Close();
??????????? cmd.Dispose();
???????????? return result;

??????? }

/// <summary>
??????? /// 查詢
??????? /// </summary>
??????? /// <returns></returns>
??????? public DataTable Select()
??????? {
??????????? SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Test;Integrated Security=True");//Initial Catalog后面跟你數據庫的名字,如果你的SqlServer服務器名稱后面不帶SQLEXPRESS，那么Data Source=.
??????????? conn.Open();???????????
??????????? string sql = "select * from users";
??????????? SqlCommand cmd = new SqlCommand(sql, conn);
??????????? SqlDataAdapter sda = new SqlDataAdapter(cmd);
??????????? DataTable dt = new DataTable();
??????????? sda.Fill(dt);??????????
??????????? conn.Close();
??????????? cmd.Dispose();
??????????? return dt;
??????? }
方法寫好后，下面舉一個查詢的例子，在form窗體中拖一個DataGridView,然后在Load方法中
??? private void Form1_Load(object sender, EventArgs e)
??????? {
????????????? dataGridView1.DataSource = Select();
??????? }
這樣一運行，DataGridView中就會顯示數據了

轉載于:https://www.cnblogs.com/qixu/p/6140677.html

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