Request Context

The DotvvmViewModelBase class contains the Context property which provides access to various DotVVM and ASP.NET resources, OWIN context etc.
It can also perform redirects, return files to be downloaded, and other things.

The DotvvmRequestContext object contains the following properties and methods:

• IsPostBack property determines whether the current request is postback, or whether the page is loaded for the first time.

• ModelState property represents the state of the model validation. You can report validation errors to the UI using this object's AddModelError method, or you can use the IsValid property to determine whether there are any validation errors in the page.

• The FailOnInvalidViewModel method checks the validity of the viewmodel and throws an exception if the viewmodel is not valid. The request execution is interrupted and the validation errors are displayed in the client's browser (e.g. in the ValidationSummary control).

• Parameters property is a dictionary which contains values of the route parameters.

• Query property is a dictionary which contains parameters from the URL query string.

• OwinContext property gives you access to the OWIN context of the current request. It's useful when you need to work with cookies, authentication etc. Please note that from DotVVM 1.1, you should use the HttpContext property or GetOwinContext() method instead of this property. This property was removed because of the ASP.NET Core support.

• RedirectToUrl and RedirectPermanentToUrl methods redirect the user to the specified URL. The request execution is interrupted by this call.

• RedirectToRoute and RedirectPermanentToRoute methods redirect the user to the specified route and allows to supply route parameters. The request execution is interrupted by this call.

• InterruptExecution interrupts the execution of the HTTP request by DotVVM and pass it to the next OWIN middleware.

• ChangeCurrentCulture changes the culture of the thread that executes the request.

• ReturnFile function is used when you need to return a file which will be downloaded by the user.