myselect.aspx.cs

ASP C#代码实例 适合初学人士学习使用

using System;
using System.Collections;
using System.Configuration;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

namespace Example_6_1
{
	/// <summary>
	/// Summary description for MySqlCommand.
	/// </summary>
	public class MySelect: System.Web.UI.Page
	{
		protected System.Web.UI.WebControls.Label ScalarLabel;
		protected System.Web.UI.WebControls.ListBox ReaderList;
		private readonly string SQLCONNECTIONSTRING = ConfigurationSettings.AppSettings["SQLCONNECTIONSTRING"].ToString();

		private void Page_Load(object sender, System.EventArgs e)
		{			
			if(!Page.IsPostBack)
			{
				///使用ExecuteScalar()方法查询数据库Staff表的记录的条数
				ScalarLabel.Text = ExecuteScalarMySqlCommand().ToString();

				///查询数据库，并显示查询结果
				ExecuteXmlReaderMySqlCommand();
			}
		}

		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion


		private object ExecuteScalarMySqlCommand()
		{
			///从数据库中获取表记录的条数
			String cmdText = "SELECT COUNT(*) from Staff";
			SqlConnection myConnection = new SqlConnection(SQLCONNECTIONSTRING);
			SqlCommand myCommand = new SqlCommand(cmdText,myConnection);

			///执行数据库查询
			myConnection.Open();
			object scalarobject = myCommand.ExecuteScalar();
			myConnection.Close();		
	
			///返回一个对象
			return(scalarobject);
		}

		private void ExecuteXmlReaderMySqlCommand()
		{
			///清空ListBox控件的所有数据项
			ReaderList.Items.Clear();

			///创建数据库的链接对象
			String cmdText = "SELECT Staff_ID,Staff_Name from Staff ORDER BY Staff_ID";
			SqlConnection myConnection = new SqlConnection(SQLCONNECTIONSTRING);
			SqlCommand myCommand = new SqlCommand(cmdText,myConnection);

			///查询数据库
			myConnection.Open();
			SqlDataReader reader = myCommand.ExecuteReader();				

			///读取SqlDataReader中的数据
			while(reader.Read())
			{
				ReaderList.Items.Add(new ListItem(reader["Staff_Name"].ToString(),reader["Staff_ID"].ToString()));				
			}

			///关闭读取器和数据库的链接
			reader.Close();
			myConnection.Close();
		}
	}
}