public bool IsExtensionAllowed(CheckExtensionMethodEnum checkExtensionMethodEnum, Stream stream, string filename) { var isExtensionAllowed = false; if (stream == null) { return(isExtensionAllowed); } switch (checkExtensionMethodEnum) { case CheckExtensionMethodEnum.MagicNumberOwnImplementation: isExtensionAllowed = CheckByOwnImplementation(stream); break; case CheckExtensionMethodEnum.ExtensionFromFileName: isExtensionAllowed = CheckByFilename(filename); break; case CheckExtensionMethodEnum.FileTypeCheckerNuget: isExtensionAllowed = FileTypeValidator.IsImage(stream); break; default: break; } return(isExtensionAllowed); }