public string WorkingFolder { get; set; }

Public Property WorkingFolder As String
	Get
	Set

Property Value

If this property is an empty string (the default value), the related files will be saved to the current folder during call of GetHtmlAndSaveRelatedFiles method; in the case of SaveHtmlAndRelatedFiles(String) method, they will be saved into the same folder where the HTML file denoted by filename parameter will be saved to.

If the message parser was configured to automatically save related files and optionally message.htm file during parsing the message (AutoSaveHtmlMode is SaveMessageHtmAndRelatedFiles or AlterHtmlBody), the effect of setting WorkingFolder will be the same as for GetHtmlAndSaveRelatedFiles method. Thus, if WorkingFolder is an empty string, related files and message.htm file will be saved in the current folder.

If GetHtmlAndSaveRelatedFiles(String, VirtualMappingType, MessageFolderBehavior) method was used to save related files and folderMode parameter value was NOT DoNotCreate, related files will be stored not directly in WorkingFolder but in its sub-folder which will be created specially for this message with unique name. This makes it possible to use the same WorkingFolder for processing multiple messages simultaneously without the risk of mixing files belonging to different messages.

Note
MessageParserConfig object cannot be used on its own. To access its members, the developer should use MailMessage.Parser property.

In case of UWP apps, this path must be accessible to the application. E.g. ApplicationData.Current.LocalFolder.Path.

Reference