实战Visual C＃数据库编程
| 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。 |
