I am developing an application in which I need multiple textboxes on the fly and one hidden text box for each textbox.

I am having problem in trapping the changed value at postback. Also there are conditions according to that the textboxes are being created means in many cases all the conditions are not matched and not all the textboxes are created and for that I have to get ids of textboxes.

That’s the problem for which I need solution.

How much do you know about the ASP.NET page life-cycle? I suspect that is where you are struggling. If you are creating WebControls on the fly, to capture events from them they have to be re-created on postback *before* viewstate is access to assign all the values to the controls on the form. This means PageLoad is too late, you need to place code in PageInit.

Here's a handy link that explains things better: