Why jmeter is not compatible with .Net application

Unfortunately, it does not works well with ASPNET, maybe because postback in the dotnet area are not the same as in the html/java/cgi-bin tradition.

In the aspnet area, the page is postback to itself, with a lot of viewstate events fired. it work well if you submit with a browser. But with a stress tool, like JMeter, or OpenSTA, this is not a browser that post a request page, but a piece of software usually running in its own thread.

ViewState: view state is nothing but .net way to keep and maintain the Form data between server request and response. For that there is Hidden text box which keep the all control information in this

Actually All HTML controls are state-less ie -these can not store any type of clients inputs when ever we send the page to server it will send this page as fresh one. so we loose the data what we have entered.

To store all these data (temporarily) in clients browsers, .Net provide a concept that is known as View state .View 

state store the data in encoding format,so that one can not guess it easily.

To retain the STATE of the server side objects BETWEEN postbacks by storing in hidden field on the page.

View state is available – after init() or before Page Load() or before On Load()

The web is stateless. But in ASP.NET, the state of a page is maintained in the in the page itself automatically. How? The values are encrypted and saved in hidden controls. this is done automatically by the ASP.NET. This can be switched off / on for a single control

A Postback is an action taken by an interactive web page, when the entire page and its contents are sent to the server for processing some information and then, the server posts the same page back to the browser.

This is done to verify passwords for logging in, process an on-line order form, or other such tasks that a client computer cannot do on its own. This is not to be confused with refresh or back actions taken by the buttons on the browser.