求一个C # 连接mysql的完整实例

[龟宝宝]

using MySQLDriverCS;我用到的引用。。。

MySQLDriverCS Exception: MySQLDriverCS Error: wrong query.No database selected

每次都是这个错误
<add name="connectionString" connectionString="Server=localhost;User Id=root;Password=;Persist Security Info=True;Database=root"/>

  MySQLConnection conn = new MySQLConnection ();

         private void Open()
         {
             conn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString; ;
             conn.Open();
         }
        public DataTable Get_Table(string sqlstr)
        {

            try
            {
                if (conn.State == ConnectionState.Closed)
                {
                    Open();
                }
                MySQLDataAdapter msd = new MySQLDataAdapter(sqlstr, conn);
                DataTable dt = new DataTable();
                msd.Fill(dt);
                return dt;
            }
            catch
            {
                return null;
            }
            
        }

sql语句是select uid from pw_members where username='人生'and password='ed5e20d12052fd90664a0f5c6ed0affc'

[cjh200102]

添加引用 mysql的dll

[快乐大法师]

MySQLDataAdapter msd = new MySQLDataAdapter(sqlstr, conn);
DataSet ds = new DataSet();
msd.Fill(ds);
return ds.Tables[0];

[Peter200694013]

http://hi.baidu.com/yinfuqing666/blog/item/0a133ed290c24f3a970a169e.html

[快乐大法师]

用这个using MySql.Data.MySqlClient;

[快乐大法师]

下一个MySql.Data.dll 添加引用

[快乐大法师]

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

namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

//创建数据库
private void button1_Click(object sender, EventArgs e)
{
MySqlConnection con = new MySqlConnection("Data Source=localhost;Initial Catalog=stuDB;User ID=root;password=root");

con.Open();


//string sql = "CREATE DATABASE stuDB";
//MySqlCommand cmd = new MySqlCommand(sql, con);
//int resulet = cmd.ExecuteNonQuery();

string sql2 = "CREATE TABLE stuinfo(stuName VARCHAR(20) NOT NULL ,stuNo CHAR(6) NOT NULL,stuAddress TEXT)";
MySqlCommand cmd = new MySqlCommand(sql2, con);
int resulet = cmd.ExecuteNonQuery();

//string sql3 = "CREATE TABLE stuinfo(stuName VARCHAR(20) NOT NULL ,stuNo CHAR(6) NOT NULL,stuAddress TEXT)";
//MySqlCommand cmd = new MySqlCommand(sql3, con);
//int resulet = cmd.ExecuteNonQuery();


con.Close();
}

//对数据库操作
private void button2_Click(object sender, EventArgs e)
{
MySqlConnection con = new MySqlConnection("Data Source=localhost;Initial Catalog=stuDB;User ID=root;password=root");

con.Open();

string sql = string.Format("insert into stuinfo(stuName,stuNo,stuAddress)values('{0}',{1},'{2}')", "dadaowangwu", 123456, "tiananmen");
MySqlCommand cmd = new MySqlCommand(sql, con);
int resulet = cmd.ExecuteNonQuery();

string sql2 = string.Format("insert into stuinfo(stuName,stuNo,stuAddress)values('{0}',{1},'{2}')", "zhangsan", 654321, "");
MySqlCommand cmd2 = new MySqlCommand(sql2, con);
int resulet2 = cmd2.ExecuteNonQuery();

string sql3 = string.Format("insert into stuinfo(stuName,stuNo,stuAddress)values('{0}',{1},'{2}')", "lisi", 986547, "huangguoshu");
MySqlCommand cmd3 = new MySqlCommand(sql3, con);
int resulet3 = cmd3.ExecuteNonQuery();

con.Close();
}
}
}

[龟宝宝]

msd.Fill(dt);
这里出现异常
MySQLDriverCS Exception: MySQLDriverCS Error: wrong query.No database selected