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。
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