Tauzilkree The Content-Type header is the one that says the browser what kind of file is being returned from the server. When you have a single instance of HttpPostedFileBase as an action parameter or a property in model then mapping the file is completely done by the HttpPostedFileBaseModelBinder and no value providers contentype used in this case. How a browser knows what file type is returned from the server? Finally we have to replace the action parameter from HttpPostedFileBase to UploadFileModel and the validations will happen automatically when the binding happens.
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Mautilar How to upload a file? In this article we learnt many things about uploading and returning files in an MVC application. POSTing a file to the server is quite simple. To understand how it generates the header see the source code. Behind the scenes 3. Note that the validation attributes applied over the File property are custom ones and not exists in the data annotations assembly.
File action-results class diagram. Learn how your comment data is processed. Step 4 Now we need to create a flieresult. Lets create a view model that wraps HttpPostedFileBase as a property which is decorated with data annotation attributes. So uploading a single file and reading it from the server is quite easy, all we need is to set the HttpPostedFileBase type as a parameter in the corresponding action method. The ContentDispositionUtil tries first to get the header value using the ContentDisposition class which is located in the System.
In the below listing we can see how to read the POSTed file from the request and save to the server. Generic ; using System.
And it will add an action ccontenttype method to the controller. AsyncUtil — C Helper class to run async methods as sync and vice-versa A useful helper class written in C Sharp to help developers working with async and sync methods in ASP. Fileresukt a browser knows what file type is returned from the server? If it fails then generate the header value based on RFC from its own methods. You can find the file in the download folder. You can see the complete code of FileContentResult here.
In the coming sections we will see how we can easily return a file as response to the clients. Creating custom file action result Creating custom validation attribute is not a difficult job! Step 6 Add a title to the index page. Notify me of new posts by email.
When we use the HttpPostedFileBase directly as action parameter then we have to validate the file manually as shown in the below listing. TryGetValue extension, out mime? When the user want to save the file sent to the browser, the server can suggest a filename to the client and the Content-Disposition header is just for that. This is an abstract class derived from ActionResult that delegates writing the file in the response to the subclasses.
MVC framework eases the job of returning files through its built-in action results. I really appreciate them. You can see the source code here. The binders are the components that really fills the properties of a model or the parameters in the action with those values. Related Posts
Get a File Content-Type / MIME-type from file extension in ASP.NET C#
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