sql注入

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;


namespace sql注入
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            object obj;
            //Data Source=.;Initial Catalog=mysql;Integrated Security=True
            string str = "Data Source =.;Initial Catalog = mysql; Integrated Security = True; ";
            //下面这种字符串拼接的方式会被   xx' or 1=1 -- 的用户名给注入，所以不能使用
            //string sql = string.Format("select count(*) from users where name = '{0}' and password = '{1}'",txtName.Text,txtPwd.Text);
            //使用参数的方法可以避免注入
            string sql = "select count(*) from users where name = @name and password = @password";
            using (SqlConnection con = new SqlConnection(str))
            {
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    con.Open();
                    //cmd使用参数
                    cmd.Parameters.AddWithValue("@name", txtName.Text);
                    cmd.Parameters.AddWithValue("@password", txtPwd.Text);
                    obj = cmd.ExecuteScalar();
                    if (Convert.ToInt32(obj) > 0)
                    {
                        MessageBox.Show("登录成功");
                    }
                    else
                    {
                        MessageBox.Show("登录失败");
                    }

                }
            }


        }
    }
}