Perform validation of the search criteria before fetchData

[boris.georgiev]

Hello,
I use a Java WebService to read data from a server. I am using regular html forms and Isomorphic ListGrid controls. I want to perform a type validation for each field passed in the search criteria according to the xml schema of the WS. I've made a method which performs this validation and works fine, but I can't figure out where I can put it so when a fetchData() is called on a ListGrid or DataSource, first to perform validation and if the validation doesn't pass I want to cancel the fetch request.

Actually I want to perform this validation for each request to the server no matter how it's performed - with callOperation or through DataSource.

[Isomorphic]

What happens if the validation fails? Typically you attach validators to a form, or to a DataSource that the form is bound to, and you call validate() when someone presses the search button.

There are other places where you could run validation, eg dataSource.transformRequest(), but it's not clear what you'd do when errors occur.