ASP.NET UpdatePanel 和 Javascript __dopostback [英] ASP.NET UpdatePanel and Javascript __dopostback

问题描述

我正在像这样从 javascript 调用部分回发:

I'm calling a partial postback from javascript like so:

function GetPolicyClick()
   {"__dopostback('UpdatePanel1', 'PostCall')";}

它完成了我需要的 1/2.它确实调用了部分回发，仅用于我的 UpdatePanel.

It does 1/2 of what I need it to. It does call a partial postback, just for my UpdatePanel.

现在是棘手的部分.我正在尝试(以某种方式)在后面的代码中引用 __dopostback 的第二个参数.这不起作用:

Now the tricky part. I'm trying (somehow) to reference the second argument of __dopostback in my code behind. This does not work:

Private Sub UpdatePanel1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles UpdatePanel1.Load

    Dim MyArg As String = Request("__EVENTARGUMENT")

End Sub

我只是得到一个空字符串.

I just get an empty string.

当然，我尝试做的事情可能是完全错误的(就像我尝试用 ASP 做的其他事情一样).我怀疑我的代码隐藏是从页面而不是面板中获取事件参数，但我真的不知道，有什么想法吗?

Of course, what I'm trying to do might be completely wrong (as with everything else I try to do with ASP). I'm suspecting that my codebehind is grabbing the event argument from the page instead of the panel, but I really don't know, Any ideas?

推荐答案

如果您想在 _EVENTARGUMENT 中放入一些值，您应该在 发送表单之前使用 javascript 执行此操作_doPostBack('UpdatePanel1','') 因为 __EVENTTARGET 是隐藏字段，在您的 html 文档中它看起来像这样:

If you want to put some value inside _EVENTARGUMENT you should do this with javascript before sending form by _doPostBack('UpdatePanel1','') because __EVENTTARGET is hidden field and in your html document it looks like this:

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

我建议你做这样的事情:

I recommend you to do something like this:

function setArgAndPostBack() {
    var arg = document.getElementById('__EVENTARGUMENT');
    var arg = document.getElementById("__EVENTARGUMENT");
    arg.value = 'something you want to put to server';
    __doPostBack('UpdatePanel1', '');
}

如果你使用 jQuery，它会更短:

If you use jQuery it would be shorter:

function setArgAndPostBack() {
    $("#__EVENTARGUMENT").val('something you want to put to server');
    __doPostBack('UpdatePanel1', '');
}

如果它不起作用，我建议您在更新面板中放置一个隐藏字段:

If it doesn't work I would like to suggest you to put one hidden field inside Update panel:

<asp:UpdatePanel runat="server" ID="UpdatePanel1">
    <ContentTemplate>
        <asp:HiddenField ID="hdnData" value="" runat="server" />
        <!-- your content goes here -->
    </ContentTemplate>
</asp:UpdatePanel>

然后做和上面一样的工作:

And then do the same work like above:

function setArgAndPostBack() {
    //Here hidden field is filled with your data
    $("#<%=hdnData.ClientID%>").val('something you want to put to server');
    __doPostBack('UpdatePanel1', '');
}

在第一种情况下，您可以在服务器端获得 __EVENTARGUMENT:

In first scenario you are able to get __EVENTARGUMENT in server side:

String args = Request["__EVENTARGUMENT"];

如果第一个场景不起作用，您可以使用类似的方法:

If first scenario doesn't work you can use something like that:

String args = hdnData.Value;//This works even in Page_Load function.

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