What is FileContentResult Asp.Net MVC? How to use FileContentResult in Asp.Net Core MVC?

 In ASP.NET MVC, the FileContentResult class is used to return binary data as a file download. It is useful when you want to return a file from your controller action, such as a PDF or an image file.

Here is an example of how to use FileContentResult in ASP.NET MVC:

csharp
public ActionResult DownloadFile()
{
    byte[] fileContents = GetFileContents(); // Retrieve the binary data of the file

    string fileName = "example.pdf"; // Set the name of the file

    return File(fileContents, "application/pdf", fileName);
}

In this example, the DownloadFile action returns a PDF file as a download. It first retrieves the binary data of the file using the GetFileContents method. It then sets the content type of the response to "application/pdf" and the file name to "example.pdf" using the File method.

You can also set additional parameters to control the behavior of the download, such as the lastModified parameter to specify the last modified date of the file, or the fileDownloadName parameter to specify a different name for the downloaded file.

csharp
public ActionResult DownloadFile()
{
    byte[] fileContents = GetFileContents(); // Retrieve the binary data of the file

    string fileName = "example.pdf"; // Set the name of the file

    DateTime lastModified = GetLastModifiedDate(); // Retrieve the last modified date of the file

    return File(fileContents, "application/pdf", fileName, lastModified, "MyDownload.pdf");
}

In this example, the DownloadFile action sets the last modified date of the file to GetLastModifiedDate() and the downloaded file name to "MyDownload.pdf".

I hope this helps you understand how to use FileContentResult in ASP.NET MVC.