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C#数据库編程2

[摘要]四.插入数据记录: </P><P>  对数据库进行插入记录操作和删除记录操作基本的思路是一致的,就是通过ADO.NET首先插入数据记录到数据库,然后对"DataSe...
四.插入数据记录: </P><P>  对数据库进行插入记录操作和删除记录操作基本的思路是一致的,就是通过ADO.NET首先插入数据记录到数据库,然后对"DataSet"对象进行必要的修改。下列代码就是以Access 2000数据库为模型修改当前记录的代码: </P><P>protected void Update_record ( object sender , System.EventArgs e )
{

int i = myBind.Position ;

try{

file://连接到一个数据库

string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb " ;

OleDbConnection myConn = new OleDbConnection ( strCon ) ;

myConn.Open ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . BeginEdit ( ) ;

file://从数据库中修改指定记录

string strUpdt = " UPDATE person SET xm = '"

+ t_xm.Text + "' , xb = '"

+ t_xb.Text + "' , nl = "

+ t_nl.Text + " , zip = "

+ t_books.Text + " WHERE id = " + t_id.Text ;

OleDbCommand myCommand = new OleDbCommand ( strUpdt , myConn ) ;

myCommand.ExecuteNonQuery ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . EndEdit ( ) ;

myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;

myConn.Close ( ) ;

}

catch ( Exception ed )

{

MessageBox.Show ( "修改指定记录错误: " + ed.ToString ( ) , "错误!" ) ;

}

myBind.Position = i ;

} </P><P>  由于对Sql Server 2000数据记录修改操作和Access 2000数据记录修改操作的差异只在于不同的数据链接,具体的代码可以参考"删除数据记录"中的代码,在这里就不提供了。



五.插入数据记录:



  和前面二种操作在思路是一致的,就是通过ADO.NET首先插入数据记录到数据库,然后对"DataSet"对象进行必要的修改。下列代码就是以Access 2000数据库为模型插入一条数据记录的代码



protected void Insert_record ( object sender , System.EventArgs e )

{

try

{

file://判断所有字段是否添完,添完则执行,反之弹出提示

if ( t_id.Text != "" && t_xm.Text != "" && t_xb.Text != "" && t_nl.Text != "" && t_books.Text != "" )

{

string myConn1 = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;

OleDbConnection myConn = new OleDbConnection ( myConn1 ) ;

myConn.Open ( ) ;

string strInsert = " INSERT INTO person ( id , xm , xb , nl , zip ) VALUES ( " ;

strInsert += t_id.Text + ", '" ;

strInsert += t_xm.Text + "', '" ;

strInsert += t_xb.Text + "', " ;

strInsert += t_nl.Text + ", " ;

strInsert += t_books.Text + ")" ;

OleDbCommand inst = new OleDbCommand ( strInsert , myConn ) ;

inst.ExecuteNonQuery ( ) ;

myConn.Close ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . BeginEdit ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . EndEdit ( ) ;

myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;

}

else

{

MessageBox.Show ( "必须填满所有字段值!" , "错误!" ) ;

}

}

catch ( Exception ed )

{

MessageBox.Show ( "保存数据记录发生 " + ed.ToString ( ) , "错误!" ) ;

}

}



  同样对Sql Server 2000数据库进行插入记录操作和Access 2000数据库插入记录操作的差异也只在于不同的数据链接,具体的代码可以参考"删除数据记录"中的代码,在这里就不提供了。

  六.Visual C#数据库编程的完成源代码和程序运行的主界面:



  掌握了上面要点,编写一个完整的数据库编程的程序就显得非常容易了,下面是Visual C#进行数据库编程的完整代码(Data01.cs),此代码是以Access 2000数据库为模型设计的,具体如下:



using System ;

using System.Drawing ;

using System.ComponentModel ;

using System.Windows.Forms ;

using System.Data.OleDb ;

using System.Data ;



public class Data : Form

{

private System.ComponentModel.Container components = null ;

private Button lastrec ;

private Button nextrec ;

private Button previousrec ;

private Button firstrec ;

private TextBox t_books ;

private TextBox t_nl ;

private ComboBox t_xb ;

private TextBox t_xm ;

private TextBox t_id ;

private Label l_books ;

private Label l_nl ;

private Label l_xb ;

private Label l_xm ;

private Label l_id ;

private Label label1 ;

private DataSet myDataSet ;

private Button button1 ;

private Button button2 ;

private Button button3 ;

private Button button4 ;

private BindingManagerBase myBind ;



public Data ( )

{

file://连接到一个数据库

GetConnected ( ) ;

// 对窗体中所需要的内容进行初始化

InitializeComponent ( ) ;

}

file://清除在程序中使用过的资源

protected override void Dispose( bool disposing )

{

if( disposing )

{

if ( components != null )

{

components.Dispose ( ) ;

}

}

base.Dispose( disposing ) ;

}

public static void Main ( )

{

Application.Run ( new Data ( ) ) ;

}

public void GetConnected ( )

{

try

{

file://创建一个 OleDbConnection

string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;

OleDbConnection myConn = new OleDbConnection ( strCon ) ;

string strCom = " SELECT * FROM person " ;

file://创建一个 DataSet

myDataSet = new DataSet ( ) ;



myConn.Open ( ) ;

file://用 OleDbDataAdapter 得到一个数据集

OleDbDataAdapter myCommand = new OleDbDataAdapter ( strCom , myConn ) ;

file://把Dataset绑定books数据表

myCommand.Fill ( myDataSet , "person" ) ;

file://关闭此OleDbConnection

myConn.Close ( ) ;

}

catch ( Exception e )

{

MessageBox.Show ( "连接错误! " + e.ToString ( ) , "错误" ) ;

}

}

private void InitializeComponent ( )

{



file://添加控件,略



this.Name = "Data" ;

this.Text = "Visual C#的数据库编程!" ;

this.ResumeLayout(false) ;

myBind = this.BindingContext [ myDataSet , "person" ] ;

}

protected void New_record ( object sender , System.EventArgs e )

{

t_id.Text = ( myBind.Count + 1 ).ToString ( ) ;

t_xm.Text = "" ;

t_xb.Text = "" ;

t_nl.Text = "" ;

t_books.Text = "" ;

}

protected void Insert_record ( object sender , System.EventArgs e )

{

try

{

file://判断所有字段是否添完,添完则执行,反之弹出提示

if ( t_id.Text != "" && t_xm.Text != "" && t_xb.Text != "" && t_nl.Text != "" && t_books.Text != "" )

{

string myConn1 = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;

OleDbConnection myConn = new OleDbConnection ( myConn1 ) ;

myConn.Open ( ) ;

string strInsert = " INSERT INTO person ( id , xm , xb , nl , zip ) VALUES ( " ;

strInsert += t_id.Text + ", '" ;

strInsert += t_xm.Text + "', '" ;

strInsert += t_xb.Text + "', " ;

strInsert += t_nl.Text + ", " ;

strInsert += t_books.Text + ")" ;

OleDbCommand inst = new OleDbCommand ( strInsert , myConn ) ;

inst.ExecuteNonQuery ( ) ;

myConn.Close ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . BeginEdit ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . EndEdit ( ) ;

myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;

}

else

{

MessageBox.Show ( "必须填满所有字段值!" , "错误!" ) ;

}

}

catch ( Exception ed )

{

MessageBox.Show ( "保存数据记录发生 " + ed.ToString ( ) , "错误!" ) ;

}

}

protected void Update_record ( object sender , System.EventArgs e )

{

int i = myBind.Position ;

try{

file://连接到一个数据库

string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb " ;

OleDbConnection myConn = new OleDbConnection ( strCon ) ;

myConn.Open ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . BeginEdit ( ) ;

file://从数据库中修改指定记录

string strUpdt = " UPDATE person SET xm = '"

+ t_xm.Text + "' , xb = '"

+ t_xb.Text + "' , nl = "

+ t_nl.Text + " , zip = "

+ t_books.Text + " WHERE id = " + t_id.Text ;

OleDbCommand myCommand = new OleDbCommand ( strUpdt , myConn ) ;

myCommand.ExecuteNonQuery ( ) ;

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . EndEdit ( ) ;

myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;

myConn.Close ( ) ;

}

catch ( Exception ed )

{

MessageBox.Show ( "修改指定记录错误: " + ed.ToString ( ) , "错误!" ) ;

}

myBind.Position = i ;

}



protected void Delete_record ( object sender , System.EventArgs e )

{

DialogResult r = MessageBox.Show ( "是否删除当前记录!" , "删除当前记录!" , MessageBoxButtons.YesNo , MessageBoxIcon.Question ) ;

int ss = ( int ) r ;

  if ( ss == 6 ) // 按动"确定"按钮

{

try{

file://连接到一个数据库

string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb " ;

OleDbConnection myConn = new OleDbConnection ( strCon ) ;

myConn.Open ( ) ;

string strDele = "DELETE FROM person WHERE id= " + t_id.Text ;

OleDbCommand myCommand = new OleDbCommand ( strDele , myConn ) ;

file://从数据库中删除指定记录

myCommand.ExecuteNonQuery ( ) ;

file://从DataSet中删除指定记录

myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . Delete ( ) ;

myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;

myConn.Close ( ) ;

}

catch ( Exception ed )

{

MessageBox.Show ( "删除记录错误信息: " + ed.ToString ( ) , "错误!" ) ;

}

}

}

file://按钮"尾记录"对象事件程序

protected void GoLast ( object sender , System.EventArgs e )

{

myBind.Position = myBind.Count - 1 ;

}



file://按钮"下一条"对象事件程序

protected void GoNext ( object sender , System.EventArgs e )

{

if ( myBind.Position == myBind.Count -1 )

MessageBox.Show ( "已经到了最后一条记录!", "信息提示!" , MessageBoxButtons.OK , MessageBoxIcon.Information ) ;

else

myBind.Position += 1 ;

}

file://按钮"上一条"对象事件程序

protected void GoPrevious ( object sender , System.EventArgs e )

{

if ( myBind.Position == 0 )

MessageBox.Show ( "已经到了第一条记录!" , "信息提示!" , MessageBoxButtons.OK , MessageBoxIcon.Information ) ;

else

myBind.Position -= 1 ;

}

file://按钮"首记录"对象事件程序

protected void GoFirst ( object sender , System.EventArgs e )

{

myBind.Position = 0 ;

}

}





  对于以Sql Server 2000数据库为模型的程序代码,只要把Data01.cs中的数据链接,即:

string myConn1 = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;



  改换成:

string strCon = "Provider = SQLOLEDB.1 ; Persist Security Info = False ; User ID = sa ; Initial Catalog = data1 ; Data Source = server1 " ;



  注释:此数据链接代表的意思是:打开Sql server数据库,服务器名称为server1,数据库为data1

就可以得到Visual C#针对Sql Server 2000数据库为模板编程的完成源程序代码了。所以本文就不再提供了。



  七.总结:



  数据库编程始终是程序编程内容中的一个重点和难点。而以上介绍的这些操作又是数据库编程中最为基本,也是最为重要的内容。那些复杂的编程无非是以上这些处理的若干个叠加。