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c# - Download file from controller RedirectToAction() - Stack Overflow
Why can't you place the RedirectToAction call where you currently return File()? – Mark Cassidy ♦ Mar 27 '17 at Indeed, I've gone with that solution and to help the performance I'm adding the pdf to the session and reading it back again since blogger.com() takes a while to generate the PDF. Apr 18, · Hello I am getting this error Message "cannot redirect after http headers have been sent" when I am calling blogger.comct ("blogger.com"). this error occured after. RedirectToAction(String) Redirects to the specified action using the action name. RedirectToAction(String, Object) Redirects to the specified action using the action name and route values. RedirectToAction(String, String) Redirects to the specified action using the action name and controller name. RedirectToAction(String, RouteValueDictionary).
Cannot redirecttoaction after file download
Uploading and returning files in an ASP. The POSTed file s are available as parameters directly in actions through model binding. The files in the cannot redirecttoaction after file download can be easily sent as response to the clients through its rich support of action results, cannot redirecttoaction after file download.
There are already plenty of articles written on this subject. So why another article? Well, cannot redirecttoaction after file download, in this article I gathered the important concepts that are scattered in different posts, threads in a single place.
I'm sure this article will help the MVC programmers to increase their grip on the framework. Thanks for all the readers who pointed out the errors and typos in the article. I really appreciate them. POSTing a file to the server is quite simple. If you forget setting the proper encoding type then only the filename is submitted not the file. In the below listing we can see how to read the POSTed file from the request and save to the server. Instead of manually reading the file from the Requestby taking the advantage of model binding the file can be made directly available as a parameter in the action as shown in the below listing.
The important cannot redirecttoaction after file download to note down is the file parameter name should be same as the name of the file input control in the above case it is photo. Prior to the. NET framework 3. But what we are interested here is to know the supporting classes. The model binding feature relies on two types of components binders and value providers. The value providers are the components that gets the value needed from the particular source query-strings, form etc.
The binders are the components that really fills the properties of a model or the parameters in the action with those values. The MVC framework is designed in such a way that these two components are loosely coupled and hence a binder don't need to worry about which value provider it has to interact to get the value for a property or parameter likewise a value provider don't need to worry about who is asking the value.
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 are used in this case.
You may think why no value providers are used in this case, it's because the source is single and clear i. Files collection. 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.
How about reading multiple files POSTed to the server? Listing 5. The important thing is the name of the file input controls should match the rules of model binding. Like any other input data the POSTed files to the server also needs validation.
For example, in the case of image we need the cannot redirecttoaction after file download should be one of the supported image types like jpg, cannot redirecttoaction after file download, jpeg, png by the server and we may also need validations to check the file size, file name etc. When we use the HttpPostedFileBase directly as action parameter then we have to validate the file manually as shown in the below listing.
In the above action we have done couple of validations against the uploaded file. Instead of doing it manually it would be great if you could do that using data annotation attributes and for that we have to use view models. Lets create a view model that wraps HttpPostedFileBase as a property which is decorated with data cannot redirecttoaction after file download attributes. Note that the validation attributes applied over the File property are custom ones and not exists in the data annotations assembly.
Creating custom validation attribute is not a difficult job! Finally we have to replace the action parameter from HttpPostedFileBase to UploadFileModel and the validations will happen automatically when the binding happens. The below listing shows the simplified version of the upload action after using view model. So far we have seen how to upload files to server and validate them using data annotations.
In the coming sections we will see how we can easily return a file as response to the clients. The Content-Type header is the one that says the browser what kind of file is being returned from the server. For some content types the browser doesn't open the save dialog and display the content directly inside its window.
Example, when you return a pdf file, some browsers knows how to display the pdf files inside it, same for images. For the content-types the browser can't display to the user it opens the save dialog ex. 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, cannot redirecttoaction after file download.
To return a file from server all we have to do is set the proper Content-TypeContent-Disposition headers and write the file into the response.
The below code snippet shows how we can return a file just plain from an action without using action results. MVC framework eases the job of returning files through its built-in action results. We don't need to worry about adding any headers in the response the action results will take care, cannot redirecttoaction after file download. This is an abstract class derived from ActionResult that delegates writing the file in the response to the subclasses.
This class contains a single abstract method called WriteFile that every subclass should implement. This class mainly does the cannot redirecttoaction after file download of adding Content-Type and Content-Disposition headers into the response.
Adding the Content-Type header is not a big deal while determining the value of the Content-Disposition header is not an easy job and the FileResult class uses a private class ContentDispositionUtil for that purpose. The ContentDispositionUtil tries first to get the header value using the ContentDisposition cannot redirecttoaction after file download which is located in the System. Mime namespace. If it fails then generate the header value based on RFC from its own methods.
To understand how it generates the header see the source code. We can even pass a file download name to the FilePathResult.
You can see the complete code of FilePathResult here. You can see the complete code of FileContentResult here. The FileStreamResult reads chunks of data from the stream and write into the response. The size of each chunk is 4KB and this can't be changed through code or config.
You can see the source code here. Actually you don't need to instantiate the FileResult types from action methods the Controller has bunch of built-in methods that helps to easily send a file in response. We can easily create new file action results by deriving from the the abstract class FileResult. For example, let see how we can create a custom action result that return files from string, let's call it FileStringResult.
We can use our FileStringResult as shown in the below action. In this article we learnt many things about uploading and returning files in an MVC application. We saw how we can apply validations to the POSTed files easily using view models.
We discussed about the different types of file action results that helps to return files from the server and even we created a custom file action result that returns a file from string. Index 1. Brief 2. How to upload a file? Reading files from request 3. HttpPostedFileBase 3. Behind the scenes 3. HttpFileCollectionValueProvider 4. Uploading multiple files 5. Using view models to validate POSTed files 5. FileSizeAttribute 5. FileTypesAttribute 6. How to return a file as response?
Cannot redirecttoaction after file download a browser knows what file type is returned from the server? Returning files through action results 7.
FileResult 7. FilePathResult 7, cannot redirecttoaction after file download. FileContentResult 7. FileStreamResult 8. Controller helper methods to return files 9. Creating custom file action result File action-results class diagram.
wordpress-how to FIX Installation failed: Download failed. error blogger.com way
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Apr 05, · I had a scenario like user would select a file from the list of the files available say page called blogger.com. The user needs to download the file once he clicks on the links.. After the download, it has to redirect to a page say blogger.com I would redirect first once the user clicked on the file name in blogger.com to blogger.com Apr 03, · Re: Redirect After returned the file Apr 02, AM | bruce (blogger.com) | LINK its not possible. the browser only takes one action per request based on the status header (only one per request). if status is a redirect a redirect is done, if its a then its a valid responose. Apr 18, · Hello I am getting this error Message "cannot redirect after http headers have been sent" when I am calling blogger.comct ("blogger.com"). this error occured after.
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