using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.SqlClient;


namespace WindowsApplication6
{
    public partial class Form1 : Form
    {
        
        public Form1()
        {
            InitializeComponent();
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Trim() == "")
            {
                MessageBox.Show("姓名不能为空");
                return;
            }
            SqlConnection cmd = new SqlConnection("server=(local);User ID=sa;pwd=;Database=zhonhouse");
            cmd.Open();
            SqlCommand cnd = new SqlCommand("select*from login ");
             = "select count(*) from login where login_name=" + textBox1.Text + " and login_pwd=" + textBox2.Text + "";
            Int32 count = (Int32)cnd.ExecuteScalar();
            if (count > 0) MessageBox.Show("ok");
        }
    }
}

启动后为什么会出现ExecuteScalar: Connection 属性尚未初始化。

   

谢了