Question

I have an ASP.NET web form where I have an hidden field, like this:

<form id="form1" runat="server" action="http://localhost/fa/Default.aspx">
        <div>
    <input id="requestData" type="hidden" name="requestData" value="" runat="server" />
    <asp:Button ID="btnPOST" Text="POST" runat="server" OnClick="do_POST" />
        </div>
    </form>

On the method do_POST I have this:

    protected void do_POST(object sender, EventArgs e)
        {
//requestDataField is of the type protected global::System.Web.UI.HtmlControls.HtmlInputHidden requestData;

            requestDataField.Text = "FOO!";
        }

When I submit the form (by pressing the button), it goes to the server (an handler) wheer I have this:

string requestData = context.Request.Form["requestData"];

I get an empty string..

But if I assign a value like this:

<input id="requestData" type="hidden" name="requestData" value="FOO" runat="server" />

I get the “FOO”

What am I missing?

Answer 1

The reason why it’s not doing it is because the method is called after the page has been post back. Meaning, it is actually working if you change .Text to .Value unfortunately by that time you have already read your form and it was an empty value. I remember working on a project where you could tell your form not to submit until a function has been run (but it was with a javascript that needed to run an complete before aspx submitted). You should try to see if there is a way to force your form to run your function BEFORE doing the postback.