原文发布时间为：2008-07-24 —— 来源于本人的百度文章 [由搬家工具导入]
首先当然要写上using System.Data.SqlClient;//这句要写上
1、建立连接字符串如下：
SqlConnection testconn = new SqlConnection("Server=.\\SQLEXPRESS;database=test;uid=sa;pwd=123456");
//SQL服务器为.\\SQLEXPRESS,数据库为test,使用sql认证方式,用户名sa,密码123456
SqlConnection testconn = new SqlConnection("Server=.\\SQLEXPRESS;database=test;Integrated Security = True");
//SQL服务器为.\\SQLEXPRESS,数据库为test,使用windows认证方式
2、写SQL语句字符串
string idsql = "SELECT * FROM stu";
string countsql="SELECT COUNT(*) FROM stu";
string textsql = "SELECT * FROM stu WHERE id=" + DropDownList1.SelectedValue;
string addsql="INSERT INTO stu VALUES('"+TextBox1.Text+"','"+TextBox2.Text+"','"+TextBox3.Text+"')";
string deletsql = "DELETE FROM stu WHERE id=" + TextBox1.Text;
string upsql = "UPDATE stu SET name='" + TextBox2.Text + "'," + "class='" + TextBox3.Text + "' WHERE id=" + TextBox1.Text;
3、添加命令
SqlCommand sid = new SqlCommand(idsql,testconn);
SqlCommand count = new SqlCommand(countsql,testconn);
SqlCommand stext = new SqlCommand(textsql, testconn);
SqlCommand addcmd = new SqlCommand(addsql, testconn);
SqlCommand deletcmd = new SqlCommand(deletsql, testconn);
SqlCommand upcmd = new SqlCommand(upsql, testconn);
4、打开连接
testconn.Open();
5、执行命令
count.ExecuteScalar();//一般增删改的命令执行都用这个吧
addcmd.ExecuteScalar();
deletcmd.ExecuteScalar();
upcmd.ExecuteScalar();
查询读取数据比较麻烦如下：
SqlDataReader testdr = sid.ExecuteReader();//执行查询时需要个dr
testdr.Read();//执行读取
testdr["列名"];//读取一个值
TextBox1.Text = textdr["id"].ToString();
TextBox2.Text = textdr["name"].ToString();
TextBox3.Text = textdr["class"].ToString();
while(testdr.Read())//testdr.Read()读出某列所有数据
{
DropDownList1.Items.Add(testdr["id"].ToString());//testdr["id"]读出id列的数据
}
textdr.Close();//最后关闭读取
6、关闭连接
testconn.Close();
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以下为本人做的完整实例代码：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;//这句要写上
public partial class _Default : System.Web.UI.Page
{
static int k;
//SqlConnection testconn = new SqlConnection("Server=.\\SQLEXPRESS;database=test;uid=sa;pwd=123456");
SqlConnection testconn = new SqlConnection("Server=.\\SQLEXPRESS;database=test;Integrated Security = True");
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
//SqlCommand sid = testconn.CreateCommand();
//SqlCommand count = testconn.CreateCommand();
//sid.CommandText = "SELECT * FROM stu";
//count.CommandText = "SELECT COUNT(*) FROM stu";
string idsql = "SELECT * FROM stu";
string countsql="SELECT COUNT(*) FROM stu";
SqlCommand sid = new SqlCommand(idsql,testconn);
SqlCommand count = new SqlCommand(countsql,testconn);
try
{
testconn.Open();
//k = (int)count.ExecuteNonQuery();
k = (int)count.ExecuteScalar();
SqlDataReader testdr = sid.ExecuteReader();
while (testdr.Read())
{
DropDownList1.Items.Add(testdr["id"].ToString());
}
testdr.Close();
}
catch (Exception ex)
{
Response.Write("<scirpt>alert('" + ex.Message.ToString() + "')</script>");
}
finally
{
testconn.Close();
}
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
string textsql = "SELECT * FROM stu WHERE id=" + DropDownList1.SelectedValue;
SqlCommand stext = new SqlCommand(textsql, testconn);
testconn.Open();
SqlDataReader textdr = stext.ExecuteReader();
textdr.Read();
TextBox1.Text = textdr["id"].ToString();
TextBox2.Text = textdr["name"].ToString();
TextBox3.Text = textdr["class"].ToString();
textdr.Close();
testconn.Close();
}
protected void Button1_Click(object sender, EventArgs e)
{
string addsql="INSERT INTO stu VALUES('"+TextBox1.Text+"','"+TextBox2.Text+"','"+TextBox3.Text+"')";
SqlCommand addcmd = new SqlCommand(addsql, testconn);
testconn.Open();
addcmd.ExecuteScalar();
testconn.Close();
Response.Redirect(".//default.aspx");
}
protected void Button2_Click(object sender, EventArgs e)
{
string deletsql = "DELETE FROM stu WHERE id=" + TextBox1.Text;
SqlCommand deletcmd = new SqlCommand(deletsql, testconn);
testconn.Open();
deletcmd.ExecuteScalar();
testconn.Close();
Response.Redirect(".//default.aspx");
}
protected void Button3_Click(object sender, EventArgs e)
{
string upsql = "UPDATE stu SET name='" + TextBox2.Text + "'," + "class='" + TextBox3.Text + "' WHERE id=" + TextBox1.Text;
SqlCommand upcmd = new SqlCommand(upsql, testconn);
testconn.Open();
upcmd.ExecuteScalar();
testconn.Close();
Response.Redirect(".//default.aspx");
}
}