如何prevent回传不使用JavaScript？ [英] How to prevent PostBack without using JavaScript?

问题描述

我有一个asp按钮 Default.aspx的：

<asp:Button ID="Button1" runat="server" Text="Button" />

和有一个程序 default.aspx.vb ：

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Panel1.Controls.Add(New LiteralControl(Date.Now))
End Sub

和老师问我，如何使完全相同的操作（当点击按钮时，显示出来的日期），但没有回传，没有JavaScript的code。我可以做一个java code有并使用的OnClientClick =返回false但似乎不对

And teacher asked me, how to make exactly same operation (when click on button, shows up a date) but without postback and without javascript code. I could make a java code there and use OnClientClick="return false" but it seems not right

推荐答案

请参阅的 ASP.Net页面的客户端

Refer The Client Side of ASP.Net Pages

你不能这样做。按钮的默认行为（输入类型=提交）是提交/后形式的url在表单的操作中指定属性。

You can't do. The default behaviour of Button(input type=submit) is to submit/post the form to the url specified in the form's action attribute.

如果您想prevent默认行为，你需要写一个javascript 返回false

If you want to prevent default behaviour you need to write a javascript return false

<asp:Button ID="btn" OnClientClick="return false" runat="server" Text="Button" />

在默认情况下asp.net发帖的形式向同一个页面本身。我们说这是回发。在浏览器中呈现的HTML查看表单标签的行动值，这将是相同的页面名称

By Default asp.net post the form to the same page itself. We say this as PostBack. See the form tags action value from rendered html in browser , it will be the same page name

<input type =submit name ="btn" id="btn" 
  onclick="javascript:__doPostBack('btn','')"value ="Button">

下列内置的JavaScript code做到这一点。

The following built in javascript code does this

<script>
                   function __doPostBack(eventTarget, eventArgument) {
                       document.Form1.__EVENTTARGET.value = eventTarget;
                       document.Form1.__EVENTARGUMENT.value = eventArgument;
                       document.Form1.submit();
                   }
</script>

您网页会自动添加下面的字​​段，序检测需要服务器端被解雇的事件。您可以在一个请求参数，如 Request.Params只需访问[__ EVENTTARGET]

Your page will have the below fields added automatically, inorder to detect which event needs to be fired in server side. you can access simply in a request parameters like Request.Params["__EVENTTARGET"]

<input type =hidden name ="__EVENTTARGET" value ="">
<input type =hidden name ="__EVENTARGUMENT" value ="">

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