How can I get the MIME type from a file extension in C#? This is a rather common question among developers, an evergreen requirement public static string GetMimeTypeByWindowsRegistry(string fileNameOrExtension). { string mimeType = "application/unknown" The MIME Type application/x-msdownload is part of the "application" category and it is commonly used to indicate the encoding for the DLL file type when such a Due to their executable nature, these file types are often put under block or restricted lists to avoid contracting an infection from these files. The XDG MIME Applications specification builds upon the #Shared MIME database and #Desktop entries to provide default applications. Applications describe what MIME types they can handle using desktop entries. desktop-file-utils registers a pacman hook to build a cache database of MIME types description: OK. schema: type: file. MIME types listed in consumes and produces should be compliant with RFC 6838. For example, you can use standard application/json application/xml application/x-www-form-urlencoded multipart/form-data text/plain; charset=utf-8 text/html application/pdf image/png. mime_types module reads mime types map specified in file option. This map contains binding. When an attachment extension matches left part but the content type does not match the right part then symbol MIME_BAD_ATTACHMENT is inserted. MediaWiki tries to detect the MIME type of the files you upload, and rejects the file if the file-extension does not match the mime type ("The file is corrupt or has an incorrect extension"). If you are getting this error for valid files, try using an external command for detecting the MIME type (see below). MIME stands for "Multipurpose Internet Mail Extensions. It's a way of identifying files on the Internet according to their nature and format. For example, using the "Content-type" header value defined in a HTTP response, the browser can open the file with the proper extension/plugin.