How to return a file filecontentresult in asp net webapi


ASP.NET is a popular programming language used for building web applications. One common in web development is the ability to return a file to the user. In this article, we will explore how to return a FileContentResult in ASP.NET Web API.

Step 1: Create a Web API Controller

To , let's create a new Web API controller in our ASP.NET project. This controller will handle the file download functionality. Here's an of how the controller might look:

public  FileController : ApiController
    public IHttpActionResult GetFile()
        // Logic to retrieve the file content
        byte[] fileContent = GetFileContent();

        // Create a FileContentResult
        var  = new FileContentResult(fileContent, "application/octet-stream")
            FileDownloadName = "example.txt"

        return ResponseMessage(fileResult);

    private byte[] GetFileContent()
        // Logic to retrieve the file content
        // This can be reading from a file, a database, or any other source
        byte[] fileContent = // Retrieve the file content here

        return fileContent;

In the above code, we have a GetFile method that retrieves the file content and creates a FileContentResult object. The FileContentResult represents a file that will be to the client. We set the content type to “application/octet-stream” and specify the file name as “example.txt”. Finally, we return the FileContentResult using the ResponseMessage method.

Step 2: Configure Web API Routing

Next, we need to configure the routing for our Web API controller. Open the WebApiConfig.cs file in your project and add the following code:

public static class WebApiConfig
    public static void (HttpConfiguration config)
        // Other configuration code...

            name: "DefaultApi",
            routeTemplate: "api/{controller}/{action}/{id}",
            defaults: new { id = RouteParameter.Optional }

In the above code, we are configuring a default for our Web API controller. This route will match URLs in the format “api/{controller}/{action}/{id}”. The “id” parameter is optional.

Step 3: Test the File Download

Now that we have our controller and routing configured, we can test the file download functionality. Start your ASP.NET project and navigate to the following URL in your :


Replace “port” with the port your project is running on. This URL will invoke the GetFile method in our FileController and return the file content as a download.


In this article, we have explored how to return a FileContentResult in ASP.NET Web API. By following the steps outlined above, you can easily implement file download functionality in your ASP.NET web application. Remember to configure the routing correctly and create a FileContentResult object with the appropriate content type and file name. Happy coding!

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