C# 查询access数据库

【核心代码】

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace MyDB
{
	/// <summary>
	/// Form1 的摘要说明。
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Panel panel1;
		private System.Windows.Forms.Splitter splitter1;
		private System.Data.OleDb.OleDbConnection oleDbConnection1;
		private System.Data.OleDb.OleDbCommand oleDbSelectCommand1;
		private System.Data.OleDb.OleDbCommand oleDbInsertCommand1;
		private System.Data.OleDb.OleDbCommand oleDbUpdateCommand1;
		private System.Data.OleDb.OleDbCommand oleDbDeleteCommand1;
		private System.Data.OleDb.OleDbDataAdapter oleDbDataAdapter1;
		private System.Data.DataSet dataSet1;
		private System.Windows.Forms.DataGrid dataGrid1;
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.Label label1;
		private System.Windows.Forms.ComboBox comboBox1;
		private System.Windows.Forms.Label label2;
		private System.Windows.Forms.TextBox textBox1;
		/// <summary>
		/// 必需的设计器变量。
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Windows 窗体设计器支持所必需的
			//
			InitializeComponent();

			//
			// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
			//
		}

		/// <summary>
		/// 清理所有正在使用的资源。
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows 窗体设计器生成的代码
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{
			this.panel1 = new System.Windows.Forms.Panel();
			this.splitter1 = new System.Windows.Forms.Splitter();
			this.oleDbConnection1 = new System.Data.OleDb.OleDbConnection();
			this.oleDbSelectCommand1 = new System.Data.OleDb.OleDbCommand();
			this.oleDbInsertCommand1 = new System.Data.OleDb.OleDbCommand();
			this.oleDbUpdateCommand1 = new System.Data.OleDb.OleDbCommand();
			this.oleDbDeleteCommand1 = new System.Data.OleDb.OleDbCommand();
			this.oleDbDataAdapter1 = new System.Data.OleDb.OleDbDataAdapter();
			this.dataSet1 = new System.Data.DataSet();
			this.dataGrid1 = new System.Windows.Forms.DataGrid();
			this.button1 = new System.Windows.Forms.Button();
			this.label1 = new System.Windows.Forms.Label();
			this.comboBox1 = new System.Windows.Forms.ComboBox();
			this.label2 = new System.Windows.Forms.Label();
			this.textBox1 = new System.Windows.Forms.TextBox();
			this.panel1.SuspendLayout();
			((System.ComponentModel.ISupportInitialize)(this.dataSet1)).BeginInit();
			((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
			this.SuspendLayout();
			// 
			// panel1
			// 
			this.panel1.Controls.Add(this.textBox1);
			this.panel1.Controls.Add(this.label2);
			this.panel1.Controls.Add(this.comboBox1);
			this.panel1.Controls.Add(this.label1);
			this.panel1.Controls.Add(this.button1);
			this.panel1.Dock = System.Windows.Forms.DockStyle.Top;
			this.panel1.Location = new System.Drawing.Point(0, 0);
			this.panel1.Name = "panel1";
			this.panel1.Size = new System.Drawing.Size(408, 40);
			this.panel1.TabIndex = 0;
			// 
			// splitter1
			// 
			this.splitter1.Dock = System.Windows.Forms.DockStyle.Top;
			this.splitter1.Location = new System.Drawing.Point(0, 40);
			this.splitter1.Name = "splitter1";
			this.splitter1.Size = new System.Drawing.Size(408, 3);
			this.splitter1.TabIndex = 1;
			this.splitter1.TabStop = false;
			// 
			// oleDbConnection1
			// 
			this.oleDbConnection1.ConnectionString = @"Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Registry Path=;Jet OLEDB:Database Locking Mode=1;Jet OLEDB:Database Password=;Data Source=""Northwind.mdb"";Password=;Jet OLEDB:Engine Type=5;Jet OLEDB:Global Bulk Transactions=1;Provider=""Microsoft.Jet.OLEDB.4.0"";Jet OLEDB:System database=;Jet OLEDB:SFP=False;Extended Properties=;Mode=Share Deny None;Jet OLEDB:New Database Password=;Jet OLEDB:Create System Database=False;Jet OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repair=False;User ID=Admin;Jet OLEDB:Encrypt Database=False";
			// 
			// oleDbSelectCommand1
			// 
			this.oleDbSelectCommand1.CommandText = "SELECT * FROM 客户 ";
			this.oleDbSelectCommand1.Connection = this.oleDbConnection1;
			// 
			// oleDbDataAdapter1
			// 
			this.oleDbDataAdapter1.DeleteCommand = this.oleDbDeleteCommand1;
			this.oleDbDataAdapter1.InsertCommand = this.oleDbInsertCommand1;
			this.oleDbDataAdapter1.SelectCommand = this.oleDbSelectCommand1;
			this.oleDbDataAdapter1.UpdateCommand = this.oleDbUpdateCommand1;
			// 
			// dataSet1
			// 
			this.dataSet1.DataSetName = "NewDataSet";
			this.dataSet1.Locale = new System.Globalization.CultureInfo("zh-CN");
			// 
			// dataGrid1
			// 
			this.dataGrid1.CaptionVisible = false;
			this.dataGrid1.DataMember = "";
			this.dataGrid1.Dock = System.Windows.Forms.DockStyle.Fill;
			this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
			this.dataGrid1.Location = new System.Drawing.Point(0, 43);
			this.dataGrid1.Name = "dataGrid1";
			this.dataGrid1.Size = new System.Drawing.Size(408, 259);
			this.dataGrid1.TabIndex = 2;
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(328, 8);
			this.button1.Name = "button1";
			this.button1.TabIndex = 0;
			this.button1.Text = "开始查询";
			this.button1.Click  = new System.EventHandler(this.button1_Click);
			// 
			// label1
			// 
			this.label1.Location = new System.Drawing.Point(8, 16);
			this.label1.Name = "label1";
			this.label1.Size = new System.Drawing.Size(96, 16);
			this.label1.TabIndex = 1;
			this.label1.Text = "选择查询条件：";
			// 
			// comboBox1
			// 
			this.comboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
			this.comboBox1.Items.AddRange(new object[] {
														   "客户ID",
														   "公司名称",
														   "联系人姓名",
														   "联系人头衔",
														   "地址",
														   "城市",
														   "地区",
														   "邮政编码",
														   "国家",
														   "电话",
														   "传真",
														   "所有记录"});
			this.comboBox1.Location = new System.Drawing.Point(96, 8);
			this.comboBox1.Name = "comboBox1";
			this.comboBox1.Size = new System.Drawing.Size(88, 20);
			this.comboBox1.TabIndex = 2;
			// 
			// label2
			// 
			this.label2.Location = new System.Drawing.Point(184, 16);
			this.label2.Name = "label2";
			this.label2.Size = new System.Drawing.Size(80, 16);
			this.label2.TabIndex = 3;
			this.label2.Text = "设置查询值：";
			// 
			// textBox1
			// 
			this.textBox1.Location = new System.Drawing.Point(256, 8);
			this.textBox1.Name = "textBox1";
			this.textBox1.Size = new System.Drawing.Size(64, 21);
			this.textBox1.TabIndex = 4;
			this.textBox1.Text = "";
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
			this.ClientSize = new System.Drawing.Size(408, 302);
			this.Controls.Add(this.dataGrid1);
			this.Controls.Add(this.splitter1);
			this.Controls.Add(this.panel1);
			this.Name = "Form1";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "演示查询Access数据库";
			this.Load  = new System.EventHandler(this.Form1_Load);
			this.Closed  = new System.EventHandler(this.Form1_Closed);
			this.panel1.ResumeLayout(false);
			((System.ComponentModel.ISupportInitialize)(this.dataSet1)).EndInit();
			((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// 应用程序的主入口点。
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void Form1_Load(object sender, System.EventArgs e)
		{//显示所有记录
			this.oleDbDataAdapter1.Fill(this.dataSet1,"客户");			
			this.dataGrid1.DataSource=this.dataSet1;	
			if(!this.dataGrid1.IsExpanded(0))
			   this.dataGrid1.Expand(0);
		}

		private void button1_Click(object sender, System.EventArgs e)
		{//查询记录
			try
			{
				this.dataSet1.Clear();							
				string StrSQL="SELECT * FROM 客户 WHERE ";
				StrSQL =this.comboBox1.Text " LIKE  '";
				StrSQL =this.textBox1.Text "'";
				if(this.comboBox1.Text=="所有记录")
					StrSQL="SELECT * FROM 客户";
				this.oleDbDataAdapter1.SelectCommand.CommandText=StrSQL;
				this.oleDbDataAdapter1.SelectCommand.Connection=this.oleDbConnection1;
				//打开数据库连接
				this.oleDbConnection1.Open();
				//执行SQL命令
				this.oleDbDataAdapter1.SelectCommand.ExecuteNonQuery();
				//关闭连接
				this.oleDbConnection1.Close();
				//更新数据集
				this.oleDbDataAdapter1.Fill(this.dataSet1,"客户");
				this.dataGrid1.DataSource=this.dataSet1;	
			}
			catch(Exception Err)
			{
				MessageBox.Show("查询数据集记录操作失败：" Err.Message,"信息提示",
					MessageBoxButtons.OK,MessageBoxIcon.Information);
				//如果打开了连接，则关闭它
				if(this.oleDbConnection1.State==ConnectionState.Open)
				{
					this.oleDbConnection1.Close();
				}
			}				
		}

		private void Form1_Closed(object sender, System.EventArgs e)
		{//关闭程序
			//如果打开了连接，则关闭它
			if(this.oleDbConnection1.State==ConnectionState.Open)
			{
				this.oleDbConnection1.Close();
			}			
		}
	}
}