用C# Builder建数据库应用程序

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　　本文主要介绍用C# Builder通过ODBC访问数据。并将数据导出到Excel,下面以C# Builder Enterprise+Microsoft Access 2000+Microsoft Excel 2000为例。

　　1.建立数据库mydb，内建表：联系人

　　联系人ID

　　名字

　　姓氏

　　地址

　　城市

　　省份

　　[ 相关贴图 ]

　　2.建立ODBC(mydb)

　　3.编写程序

　　点击菜单 File - New - C# Application,输入应用程序名称

　　如果还没有安装ODBC组件，你还需要装上它们。点击菜单Component - Installed .Net components，在Installed .Net components窗口中确定ODBC组件已经选上。确定后，看tool Palette上是否有ODBC几个组件在上面。图示

　　加上一个OdbcConnection和一个OdbcCommand

　　选中odbcConnection1，在ConnectionString输入：DSN=mydb;Uid=admin;Pwd=;

　　选中odbcCommand1,Connection选择odbcConnection1,CommandText输入：select * from 联系人

　　WinForm窗口加上两个Button和ListBox，其中ListBox的Dock设为Bottom

　　双击按钮，输入代码：

listBox1.Items.Clear();odbcConnection1.Open();OdbcDataReader myreader=odbcCommand1.ExecuteReader();try{while (myreader.Read()){listBox1.Items.Add(myreader.GetString(0)+","+myreader.GetString(1)+" "+myreader.GetString(2));}}finally{myreader.Close();odbcConnection1.Close();}

　　对于.NET对ODBC的一些使用方法，可以查看帮助。上面写得很详细。

　　通过Com组件来完成数据导出Excel：

　　为了在C#中使用Excel，我们要先做一点准备工作，在你的计算机中找到TlbImp和Excel9.olb，将他们复制到一个文件夹中，在DOS窗口中执行 TlbImp Excel9.olb，这时会产生以下三个文件：Excel.dll、Office.dll和VBIDE.dll。

　　通过菜单 project-Add reference ，弹出的对话框中选择COM imports，点击Browser按钮,选中前面生成的三个DLL文件，OK

　　导出代码如下：

//创建一个Excel文件int i;Excel.Application myExcel = new Excel.Application ( ) myExcel.Application.Workbooks.Add ( true ) //让Excel文件可见myExcel.Visible=true;//第一行为报表名称myExcel.Cells[1,4]="联系人";myExcel.Cells[2,1]="联系人ID";myExcel.Cells[2,2]="名字";myExcel.Cells[2,3]="姓氏";myExcel.Cells[2,4]="地址";myExcel.Cells[2,5]="城市";myExcel.Cells[2,6]="省份";//逐行写入数据，listBox1.Items.Clear();odbcConnection1.Open();OdbcDataReader myreader=odbcCommand1.ExecuteReader();try{i=2;while (myreader.Read()){i=i+1;myExcel.Cells[i,1]=myreader.GetString(0);myExcel.Cells[i,2]=myreader.GetString(1);myExcel.Cells[i,3]=myreader.GetString(2);myExcel.Cells[i,4]=myreader.GetString(3);myExcel.Cells[i,5]=myreader.GetString(4);myExcel.Cells[i,6]=myreader.GetString(5);}}finally{myreader.Close();odbcConnection1.Close();}

　　程序完整的代码如下：

using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;using System.Data;using System.Data.Odbc;using System.IO;using System.Reflection;namespace DBApp{/// summary/// Summary description for WinForm./// /summarypublic class WinForm : System.Windows.Forms.Form{/// summary/// Required designer variable./// /summaryprivate System.ComponentModel.Container components = null;private System.Data.Odbc.OdbcConnection odbcConnection1;private System.Data.Odbc.OdbcCommand odbcCommand1;private System.Windows.Forms.ListBox listBox1;private System.Windows.Forms.Button button1;private System.Windows.Forms.Button button2;public WinForm(){//// Required for Windows Form Designer support//InitializeComponent();//// TODO: Add any constructor code after InitializeComponent call//}/// summary/// Clean up any resources being used./// /summaryprotected override void Dispose (bool disposing){if (disposing){if (components != null){components.Dispose();}}base.Dispose(disposing);}#region Windows Form Designer generated code/// summary/// Required method for Designer support - do not modify/// the contents of this method with the code editor./// /summaryprivate void InitializeComponent(){this.odbcConnection1 = new System.Data.Odbc.OdbcConnection();this.listBox1 = new System.Windows.Forms.ListBox();this.button1 = new System.Windows.Forms.Button();this.odbcCommand1 = new System.Data.Odbc.OdbcCommand();this.button2 = new System.Windows.Forms.Button();this.SuspendLayout();//// odbcConnection1//this.odbcConnection1.ConnectionString = "DSN=mydb;Uid=admin;Pwd=;";//// listBox1//this.listBox1.Dock = System.Windows.Forms.DockStyle.Bottom;this.listBox1.ItemHeight = 12;this.listBox1.Location = new System.Drawing.Point(0, 53);this.listBox1.Name = "listBox1";this.listBox1.Size = new System.Drawing.Size(368, 184);this.listBox1.TabIndex = 0;//// button1//this.button1.Location = new System.Drawing.Point(16, 16);this.button1.Name = "button1";this.button1.TabIndex = 1;this.button1.Text = "查询";this.button1.Click += new System.EventHandler(this.button1_Click);//// odbcCommand1//this.odbcCommand1.CommandText = "select * from 联系人 ";this.odbcCommand1.Connection = this.odbcConnection1;//// button2//this.button2.Location = new System.Drawing.Point(245, 14);this.button2.Name = "button2";this.button2.TabIndex = 2;this.button2.Text = "导出";this.button2.Click += new System.EventHandler(this.button2_Click);//// WinForm//this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);this.ClientSize = new System.Drawing.Size(368, 237);this.Controls.Add(this.button2);this.Controls.Add(this.button1);this.Controls.Add(this.listBox1);this.Name = "WinForm";this.Text = "WinForm";this.Load += new System.EventHandler(this.WinForm_Load);this.ResumeLayout(false);}#endregion/// summary/// The main entry point for the application./// /summary[STAThread]static void Main(){Application.Run(new WinForm());}private void WinForm_Load(object sender, System.EventArgs e){}private void button1_Click(object sender, System.EventArgs e){listBox1.Items.Clear();odbcConnection1.Open();OdbcDataReader myreader=odbcCommand1.ExecuteReader();try{while (myreader.Read()){listBox1.Items.Add(myreader.GetString(0)+","+myreader.GetString(1)+" "+myreader.GetString(2));}}finally{myreader.Close();odbcConnection1.Close();}}private void button2_Click(object sender, System.EventArgs e){//创建一个Excel文件int i;Excel.Application myExcel = new Excel.Application ( ) myExcel.Application.Workbooks.Add ( true ) //让Excel文件可见myExcel.Visible=true;//第一行为报表名称myExcel.Cells[1,4]="联系人";myExcel.Cells[2,1]="联系人ID";myExcel.Cells[2,2]="名字";myExcel.Cells[2,3]="姓氏";myExcel.Cells[2,4]="地址";myExcel.Cells[2,5]="城市";myExcel.Cells[2,6]="省份";//逐行写入数据，listBox1.Items.Clear();odbcConnection1.Open();OdbcDataReader myreader=odbcCommand1.ExecuteReader();try{i=2;while (myreader.Read()){i=i+1;myExcel.Cells[i,1]=myreader.GetString(0);myExcel.Cells[i,2]=myreader.GetString(1);myExcel.Cells[i,3]=myreader.GetString(2);myExcel.Cells[i,4]=myreader.GetString(3);myExcel.Cells[i,5]=myreader.GetString(4);myExcel.Cells[i,6]=myreader.GetString(5);}}finally{myreader.Close();odbcConnection1.Close();}}}}

　　4.运行程序

　　按F9运行程序