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四．插入數(shù)據(jù)記錄： </P><P> 對數(shù)據(jù)庫進(jìn)行插入記錄操作和刪除記錄操作基本的思路是一致的，就是通過ADO.NET首先插入數(shù)據(jù)記錄到數(shù)據(jù)庫，然后對"DataSet"對象進(jìn)行必要的修改。下列代碼就是以Access 2000數(shù)據(jù)庫為模型修改當(dāng)前記錄的代碼： </P><P>protected void Update_record ( object sender , System.EventArgs e )
{
int i = myBind.Position ;
try{
file://連接到一個數(shù)據(jù)庫
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://從數(shù)據(jù)庫中修改指定記錄
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 ( "修改指定記錄錯誤： " + ed.ToString ( ) , "錯誤！" ) ;
}
myBind.Position = i ;
} </P><P> 由于對Sql Server 2000數(shù)據(jù)記錄修改操作和Access 2000數(shù)據(jù)記錄修改操作的差異只在于不同的數(shù)據(jù)鏈接，具體的代碼可以參考"刪除數(shù)據(jù)記錄"中的代碼，在這里就不提供了。
五．插入數(shù)據(jù)記錄：
和前面二種操作在思路是一致的，就是通過ADO.NET首先插入數(shù)據(jù)記錄到數(shù)據(jù)庫，然后對"DataSet"對象進(jìn)行必要的修改。下列代碼就是以Access 2000數(shù)據(jù)庫為模型插入一條數(shù)據(jù)記錄的代碼
protected void Insert_record ( object sender , System.EventArgs e )
{
try
{
file://判斷所有字段是否添完，添完則執(zhí)行，反之彈出提示
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 ( "必須填滿所有字段值！" , "錯誤！" ) ;
}
}
catch ( Exception ed )
{
MessageBox.Show ( "保存數(shù)據(jù)記錄發(fā)生 " + ed.ToString ( ) , "錯誤！" ) ;
}
}
同樣對Sql Server 2000數(shù)據(jù)庫進(jìn)行插入記錄操作和Access 2000數(shù)據(jù)庫插入記錄操作的差異也只在于不同的數(shù)據(jù)鏈接，具體的代碼可以參考"刪除數(shù)據(jù)記錄"中的代碼，在這里就不提供了。
六．Visual C＃數(shù)據(jù)庫編程的完成源代碼和程序運(yùn)行的主界面：
掌握了上面要點(diǎn)，編寫一個完整的數(shù)據(jù)庫編程的程序就顯得非常容易了，下面是Visual C＃進(jìn)行數(shù)據(jù)庫編程的完整代碼（Data01.cs），此代碼是以Access 2000數(shù)據(jù)庫為模型設(shè)計(jì)的，具體如下：
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://連接到一個數(shù)據(jù)庫
GetConnected ( ) ;
// 對窗體中所需要的內(nèi)容進(jìn)行初始化
InitializeComponent ( ) ;
}
file://清除在程序中使用過的資源
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://創(chuàng)建一個 OleDbConnection
string strCon = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;
OleDbConnection myConn = new OleDbConnection ( strCon ) ;
string strCom = " SELECT * FROM person " ;
file://創(chuàng)建一個 DataSet
myDataSet = new DataSet ( ) ;
myConn.Open ( ) ;
file://用 OleDbDataAdapter 得到一個數(shù)據(jù)集
OleDbDataAdapter myCommand = new OleDbDataAdapter ( strCom , myConn ) ;
file://把Dataset綁定books數(shù)據(jù)表
myCommand.Fill ( myDataSet , "person" ) ;
file://關(guān)閉此OleDbConnection
myConn.Close ( ) ;
}
catch ( Exception e )
{
MessageBox.Show ( "連接錯誤! " + e.ToString ( ) , "錯誤" ) ;
}
}
private void InitializeComponent ( )
{
file://添加控件，略
this.Name = "Data" ;
this.Text = "Visual C＃的數(shù)據(jù)庫編程！" ;
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://判斷所有字段是否添完，添完則執(zhí)行，反之彈出提示
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 ( "必須填滿所有字段值！" , "錯誤！" ) ;
}
}
catch ( Exception ed )
{
MessageBox.Show ( "保存數(shù)據(jù)記錄發(fā)生 " + ed.ToString ( ) , "錯誤！" ) ;
}
}
protected void Update_record ( object sender , System.EventArgs e )
{
int i = myBind.Position ;
try{
file://連接到一個數(shù)據(jù)庫
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://從數(shù)據(jù)庫中修改指定記錄
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 ( "修改指定記錄錯誤： " + ed.ToString ( ) , "錯誤！" ) ;
}
myBind.Position = i ;
}
protected void Delete_record ( object sender , System.EventArgs e )
{
DialogResult r = MessageBox.Show ( "是否刪除當(dāng)前記錄！" , "刪除當(dāng)前記錄！" , MessageBoxButtons.YesNo , MessageBoxIcon.Question ) ;
int ss = ( int ) r ;
if ( ss == 6 ) // 按動"確定"按鈕
{
try{
file://連接到一個數(shù)據(jù)庫
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://從數(shù)據(jù)庫中刪除指定記錄
myCommand.ExecuteNonQuery ( ) ;
file://從DataSet中刪除指定記錄
myDataSet.Tables [ "person" ] . Rows [ myBind.Position ] . Delete ( ) ;
myDataSet.Tables [ "person" ] . AcceptChanges ( ) ;
myConn.Close ( ) ;
}
catch ( Exception ed )
{
MessageBox.Show ( "刪除記錄錯誤信息： " + ed.ToString ( ) , "錯誤！" ) ;
}
}
}
file://按鈕"尾記錄"對象事件程序
protected void GoLast ( object sender , System.EventArgs e )
{
myBind.Position = myBind.Count - 1 ;
}
file://按鈕"下一條"對象事件程序
protected void GoNext ( object sender , System.EventArgs e )
{
if ( myBind.Position == myBind.Count -1 )
MessageBox.Show ( "已經(jīng)到了最后一條記錄！", "信息提示！" , MessageBoxButtons.OK , MessageBoxIcon.Information ) ;
else
myBind.Position += 1 ;
}
file://按鈕"上一條"對象事件程序
protected void GoPrevious ( object sender , System.EventArgs e )
{
if ( myBind.Position == 0 )
MessageBox.Show ( "已經(jīng)到了第一條記錄！" , "信息提示！" , MessageBoxButtons.OK , MessageBoxIcon.Information ) ;
else
myBind.Position -= 1 ;
}
file://按鈕"首記錄"對象事件程序
protected void GoFirst ( object sender , System.EventArgs e )
{
myBind.Position = 0 ;
}
}
對于以Sql Server 2000數(shù)據(jù)庫為模型的程序代碼，只要把Data01.cs中的數(shù)據(jù)鏈接，即：
string myConn1 = " Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source = db.mdb" ;
改換成：
string strCon = "Provider = SQLOLEDB.1 ; Persist Security Info = False ; User ID = sa ; Initial Catalog = data1 ; Data Source = server1 " ;
注釋：此數(shù)據(jù)鏈接代表的意思是：打開Sql server數(shù)據(jù)庫，服務(wù)器名稱為server1,數(shù)據(jù)庫為data1
就可以得到Visual C＃針對Sql Server 2000數(shù)據(jù)庫為模板編程的完成源程序代碼了。所以本文就不再提供了。
七．總結(jié)：
數(shù)據(jù)庫編程始終是程序編程內(nèi)容中的一個重點(diǎn)和難點(diǎn)。而以上介紹的這些操作又是數(shù)據(jù)庫編程中最為基本，也是最為重要的內(nèi)容。那些復(fù)雜的編程無非是以上這些處理的若干個疊加。
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