ASP.NET MVC: Displaying a PDF Document in the Browser

Returning a pdf document (or any file for that matter) is very simple using ASP.NET MVC due to the fact that action methods can return a result of type FileResult or FilePathResult. To return a file stored in the App_Data directory, simply do the following:

public FileResult GetFile(string fileName)
{
    string path = AppDomain.CurrentDomain.BaseDirectory + "App_Data/";            
    return File(path + fileName, System.Net.Mime.MediaTypeNames.Application.Pdf, fileName);
}

But, despite the fact that we have indicated that the MIME type is ‘application/pdf’, the user will be prompted with a download dialog box instead of the pdf simply being displayed in the browser. This is a shortcoming in the ASP.NET MVC framework that can be fixed by adding a line to the header of the response. To make the browser display the pdf file, add the following line of code to your action method:

public FileResult GetFile(string fileName)
{
    // Force the pdf document to be displayed in the browser
    Response.AppendHeader("Content-Disposition", "inline; filename=" + fileName + ";");

    string path = AppDomain.CurrentDomain.BaseDirectory + "App_Data/";            
    return File(path + fileName, System.Net.Mime.MediaTypeNames.Application.Pdf, fileName);
}

Adding the value ‘inilne’ to the Content-Disposition attribute indicates to the browser that it should be displayed immediately rather than downloaded by the user.