Hi,
I don't think there's any limitation in terms of how many input parameters you can create. You can create as many as you want if necessary. If you run into any issues when creating further input parameters, I would suggest you to raise a support ticket.
>While triggering service it receive all 200 input parameters simultaneously (or) one by one.?
200 input parameters has to be passed every time when calling the service with 200 input parameters defined. If no data passed, it will use default value or undefined for the input parameters.
For passing values from text box to the service, at the time the text box's text is changed, the data is passed to the bound input parameter. If all the necessary text box value has entered, you can use a button click event to trigger the execution of the service.
If 200 inputs are really required for some reasons to achieve the business logic, it might be more manageable if you pass in infotable data and retrieve row data from the infotable, in turn retrieve field data for processing.
Best,
Tony