ASP.NET如何在用戶端調用服務端代碼

最後更新：2018-12-07 來源：互聯網

上載者：User

創建阿里雲帳戶，並獲得超過 40 款產品的免費試用版；而企業帳戶則可以享有總值 $1200 的免費試用版。立即註冊！

摘自：http://www.dnnstudy.com/Default.aspx?tabid=52&ctl=Detail&mid=403&Id=1640http://blog.csdn.net/xujh/

比如我們在頁面上有3個TextBox，3個Button，每個Button分別執行不同的動作。我們現在想在TextBox中檢測是否按下了斷行符號鍵，如果是則執行不同的Button調用。即TextBox1中按下斷行符號就執行Button1的動作,......

測試中，我發現要調用伺服器端代碼必須調用__doPostBack函數，但該函數除了在放置有DataGrid控制項的頁面中會由系統產生外，其他的頁面中並不存在。（可以通過查看源檔案看到該代碼）。這樣我們必須手工在aspx中添加__doPostBack函數，和函數一起添加的還有兩個隱藏元素，__EVENTTARGET和__EVENTARGUMENT，這是__doPostBack所必須的，實際上，.NET是把產生事件的元素名稱以及參數傳到，__EVENTTARGET和__EVENTARGUMENT。然後再調用Form的submit函數提交回伺服器的，伺服器端根據傳回來的參數就知道是哪個控制項被觸發了，從而調用它的相應後端代碼，然後再將新頁面回送回用戶端的。
以下是我的測試頁面，其中使用了兩種方法來檢測TextBox中的按鍵
WebForm2.aspx
--------------------------------------------------------
<%@ Page language="c#" Codebehind="WebForm2.aspx.cs" AutoEventWireup="false" Inherits="UTF8Test.WebForm2" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
  <title>WebForm2</title>
  <meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
  <meta content="C#" name="CODE_LANGUAGE">
  <meta content="javascript" name="vs_defaultClientScript">
  <meta content="http://schemas.microsoft.com/intellisense/ie5"; name="vs_targetSchema">
  <script language="javascript" event="onkeydown" for="TextBox1">

if(event.keyCode==13)
   {
    __doPostBack('Button1','');
    return false;
   }

  </script>
  <script language="javascript" event="onkeydown" for="TextBox2">

if(event.keyCode==13)
   {
    __doPostBack('Button2','');
    return false;
   }

  </script>
  <script language="javascript">
    function keypress()
    {
     if(event.keyCode==13)
   {

    __doPostBack('Button3','');
    event.keyCode=0; 
    return false;
   }
    }
  </script>
</HEAD>
<body MS_POSITIONING="GridLayout">
  <form id="Form1" method="post" runat="server">
   <input type="hidden" name="__EVENTTARGET"> <input type="hidden" name="__EVENTARGUMENT">
   <script language="javascript" type="text/javascript">

   </script>
   <asp:button id="Button1" style="Z-INDEX: 101; LEFT: 192px; POSITION: absolute; TOP: 88px" runat="server"
    Text="Button1"></asp:button><asp:textbox id="TextBox1" style="Z-INDEX: 102; LEFT: 16px; POSITION: absolute; TOP: 88px" runat="server"></asp:textbox>
   <asp:Button id="Button2" style="Z-INDEX: 103; LEFT: 192px; POSITION: absolute; TOP: 120px" runat="server"
    Text="Button2"></asp:Button>
   <asp:TextBox id="TextBox2" style="Z-INDEX: 104; LEFT: 16px; POSITION: absolute; TOP: 120px" runat="server"></asp:TextBox>
   <asp:TextBox id="TextBox3" style="Z-INDEX: 105; LEFT: 16px; POSITION: absolute; TOP: 152px" runat="server"></asp:TextBox>
   <asp:Button id="Button3" style="Z-INDEX: 106; LEFT: 192px; POSITION: absolute; TOP: 152px" runat="server"
    Text="Button3"></asp:Button>
   <asp:Label id="Label1" style="Z-INDEX: 107; LEFT: 24px; POSITION: absolute; TOP: 56px" runat="server"></asp:Label></form>
</body>
</HTML>

WebForm2.aspx.cs
----------------------------------------------------------------------
using System;
using System.Collections;
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;

namespace UTF8Test
{
/// <summary>
/// WebForm2 的摘要說明。
/// </summary>
public class WebForm2 : System.Web.UI.Page
{
  protected System.Web.UI.WebControls.TextBox TextBox1;
  protected System.Web.UI.WebControls.Button Button2;
  protected System.Web.UI.WebControls.TextBox TextBox2;
  protected System.Web.UI.WebControls.TextBox TextBox3;
  protected System.Web.UI.WebControls.Button Button3;
  protected System.Web.UI.WebControls.Label Label1;
  protected System.Web.UI.WebControls.Button Button1;

  private void Page_Load(object sender, System.EventArgs e)
  {
   // 在此處放置使用者代碼以初始化頁面
   TextBox3.Attributes.Add("onkeypress","keypress()");//注意大小寫
  }

  #region Web 表單設計器產生的程式碼
  override protected void OnInit(EventArgs e)
  {
   //
   // CODEGEN: 該調用是 ASP.NET Web 表單設計器所必需的。
   //
   InitializeComponent();
   base.OnInit(e);
  }

  /// <summary>
  /// 設計器支援所需的方法 - 不要使用代碼編輯器修改
  /// 此方法的內容。
  /// </summary>
  private void InitializeComponent()
  {
   this.Button1.Click += new System.EventHandler(this.Button1_Click);
   this.Button2.Click += new System.EventHandler(this.Button2_Click);
   this.Button3.Click += new System.EventHandler(this.Button3_Click);
   this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

  private void Button1_Click(object sender, System.EventArgs e)
  {
   Label1.Text = "1";
  }

  private void Button2_Click(object sender, System.EventArgs e)
  {
   Label1.Text = "2";
  }

  private void Button3_Click(object sender, System.EventArgs e)
  {
   Label1.Text = "3";
  }
}
}

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

Sales Support

1 on 1 presale consultation

Chat Contact Sales
After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

Open a Ticket
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

Learn More

ASP.NET如何在用戶端調用服務端代碼

聯繫我們

A Free Trial That Lets You Build Big!

Sales Support

After-Sales Support