c# 连接数据库

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

namespace sql连接数据库demo
{
public partial class Form1 : Form
{
public string connStr = "Data Source=LIUHENG\\SQL2005L;Initial Catalog=webTest;User ID=sa;Password=liuheng0429";
public SqlConnection conn;
public SqlCommand cmd;
public Form1()
{
InitializeComponent();
this.Text = "sql连接数据库";
}

private void button1_Click(object sender, EventArgs e)
{

if (textBox1.Text != "")
{
string sqlText = "insert into house(typeS) values('" + textBox1.Text + "')";

int i = ExecuteNonQuery(sqlText);

if (i > 0)
{
MessageBox.Show("添加完成");
dataGridView1.DataSource = GetData().DefaultView;
}
else
{
MessageBox.Show("添加失败");
}
}
}

private void button3_Click(object sender, EventArgs e)
{

dataGridView1.DataSource = GetData().DefaultView;
}

private DataTable GetData()
{
return GetTable("select * from house order by id desc ");

}

#region 数据库操作
/// <summary>
/// 打开链接
/// </summary>
/// <returns></returns>
private SqlConnection GetConn()
{
if (conn == null) conn = new SqlConnection(connStr);
if (conn.State == ConnectionState.Closed) conn.Open();
else if (conn.State == ConnectionState.Broken)
{
conn.Close();
conn.Open();
}

return conn;
}

/// <summary>
/// 执行增删改查操作
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
private int ExecuteNonQuery(string sql)
{
try
{
cmd = new SqlCommand(sql, GetConn());
return cmd.ExecuteNonQuery();
}
catch
{
return 0;
}
finally
{
conn.Close();
}
}
/// <summary>
/// 读数据
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
private SqlDataReader ExecuteReader(string sql)
{
try
{
cmd = new SqlCommand(sql, GetConn());
return cmd.ExecuteReader();
}
catch
{
return null;
}
finally
{
conn.Close();
}
}
/// <summary>
/// 得到该表数据
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
private DataTable GetTable(string sql)
{
try
{
SqlDataAdapter da = new SqlDataAdapter(sql, GetConn());
DataSet ds = new DataSet();
da.Fill(ds);
return ds.Tables[0];
}
catch
{
return null;
}
finally
{
conn.Close();
}
}
#endregion

private void button2_Click(object sender, EventArgs e)
{
if (textBox2.Text != "")
{

int i = ExecuteNonQuery("delete house where id = " + textBox2.Text);
if (i > 0)
{
MessageBox.Show("删除成功");
dataGridView1.DataSource = GetData().DefaultView;
}
else
{
MessageBox.Show("删除失败");
}
}
}
}

}