Why is my Asp.Net Form arriving empty when I post from Page to Page?

StackOverflow https://stackoverflow.com/questions/2433624

  •  19-09-2019
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Question

I have the following HTML Code

<%@ Page Language="C#" %>

<html>
    <head>
        <title></title>
    </head>
    <body>
        <form id="frmSystem" method="post" action="target.aspx">
            <input id="txtTextField" type="text" />
            <input id="btnPost" value="Submit" onclick="javascript:frmSystem.submit();" type="button" />
        </form>
    </body>
</html>

The target Page is coming up but the form that it is receiving is empty. I have a break point on my target.aspx page and while I can see a form, it's keys are empty and Request["txtTextField"] gives me nothing.

Any clue why?

Was it helpful?

Solution

If you are using ASP.NET MVC, the input names need to be set with the "name" attribute rather than "id".

OTHER TIPS

If you are using ASP.NET 4.5 like me, use below hints

  • Disable auto Friendly URLs in a Web Form project
    • settings.AutoRedirectMode = RedirectMode.Off; // in RouteConfig.cs
  • if you can:
    • remove action="CILandingPage.aspx" from form element
    • put a asp:button instead of normal button
    • set PostBackUrl="~/CILandingPage.aspx" on your asp:button

more resources with more detail that was useful to me

You probably reset the form value in event handlers (such as page_load).

Another option is to capture your Request.Form[] data in Application_BeginRequest on the Global.asax.cs:

protected void Application_BeginRequest(object sender, EventArgs e)
{
    //capture form data and preserve in query string
    if (Request.Form["txtTextField"]!= null)
    {
        Response.Redirect(Request.RawUrl + "?txtTextField=" 
          + Request.Form["txtTextField"]);
    }
    //or preserve in Session variable
    if(Request.Form["txtTextField"]!=null)
    {
        Session["txtTextField"]=Request.Form["txtTextField"];
    }
}

The problem is that the form data is lost on the automatic redirect which is applied by friendlyUrls - if you store that data as something other than form data, it is unnecessary to turn off friendlyUrls or set AutoRedirectMode to RedirectMode.Off.

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