如果你是上面这一段代码,是这样放置的:using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace MDI // 命名空间
{
public partial class DanPinFX : Form //类
{
public DanPinFX()
{
InitializeComponent();
} public int sdllj() //自己创建的函数
{
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close();
} }
}
看得懂意思了不?
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace MDI // 命名空间
{
public partial class DanPinFX : Form //类
{
public DanPinFX()
{
InitializeComponent();
} public int sdllj() //自己创建的函数
{
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close();
} }
}
看得懂意思了不?
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private void button2_Click(object sender, EventArgs e)
{}
public void Form2_Load(object sender, EventArgs e)
{
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close();
}
但是在:
private void button2_Click(object sender, EventArgs e)
{
DataTable tdt = tds.Tables[0];
DataRow r1 = tds.Tables[0].Rows[0];
}
中tds不能用;
需要这个培训视频的朋友请联系 QQ 936652114
tda.Fill(tds);
可以写在
private void button2_Click(object sender, EventArgs e)
{
} 里面不
把连接数据库的代码都放里面;
在同一名字空间用 类名.tds 访问 或 名字空间.类名.tds
我这样并不是在web编程里面,windows是这样的. C# code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace MDI // 命名空间
{
public partial class DanPinFX : Form //类
{
public DanPinFX()
{
InitializeComponent();
} public int sdllj() //自己创建的函数
{
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close();
} private void button2_Click(object sender, EventArgs e)
{
sdllj() //调用这个自建的函数就可以了.里面的内容你可以自己设计;
}
}
}
DataSet tds = new DataSet();
tda.Fill(tds);
可以写在
private void button2_Click(object sender, EventArgs e)
{
} 里面不 ?
这个问题,我的回答是:当然可以啊!
SqlHelper+Dto+Business+UI
------------------------------
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close(); ------------------
把上面的整理好,
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn; 放sqlhelper层去,
---------------------------SELECT * FROM T2放Dto层去,
------------------
不知道LZ是否这个意思?
献丑了...
需要这个培训视频的朋友请联系 QQ 936652114
String connectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=";
connectionString += @"e:\teacher\data\teacher.mdb";
OleDbConnection conn = new OleDbConnection(connectionString);
上面这二句做成公用变量,在程序初始化的时候就可以了.
下面这些都是在使用的时候就调用,至于封装成类那就看数据操作的量多不多喽,要是多的话可以封装,不然就没必要了.
conn.Open();
OleDbCommand selcmd = new OleDbCommand();
selcmd.Connection = conn;
selcmd.CommandText = "SELECT * FROM T2";
OleDbDataAdapter tda = new OleDbDataAdapter();
tda.SelectCommand = selcmd;
DataSet tds = new DataSet();
tda.Fill(tds);
conn.Close();
放在方法体外面,设置成公共变量,tds就可以任你蹂躏了