From your description, the issue happens when calling server method from client-side. Does this term mean that you try to invoke WebFlyPostBackMethod from client side?

By chance, I have been working on a project that – I think – has identical scenario. I have a webform where when user select a row from WebGrid, the data key value of the selected row will be passed as query string.

The query string is consumed by another webform. OnPageLoad event, the data key value is retrieved from query string by using following line.

if (!IsPostBack)
{
    ClientScript.RegisterHiddenField("keyValue", Request["keyValue"]);
    ClientScript.RegisterHiddenField("state", Request["state"]);
    ...

Perhaps you should ensure that you have added WebFlyPostBackListener instance during page load.

WebFlyPostBackListener listener;
    
protected void Page_Load(object sender, EventArgs e)
{
    listener = new WebFlyPostBackListener(this);
    ...

Hope this helps.

Hi yudi. that's not what the issue was at all.

The solution was to explicitly set the webflypostbackmanager's serviceUrl on server side during page load event to include the querystring.

Glad to hear the good news.

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