.NET开发：用C# Builder建数据库应用程序

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用C# Builder建数据库应用程序

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作者：徐长友主页:http://yousoft.hi.com.cn
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，内建一表：联系人
联系人ID
名字
姓氏
地址
城市
省份

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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

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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

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加上一个OdbcConnection和一个OdbcCommand

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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。

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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.
/// </summary>
public class WinForm : System.Windows.Forms.Form
{
  /// <summary>
  /// Required designer variable.
  /// </summary>
  private 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.
  /// </summary>
  protected 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.
  /// </summary>
  private 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

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示例代码：

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