WindowsPreviewHandlerMBS.Constructor(ClassID as string)

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Initializes the object with loading the class with the given classid.

You find those ClassIDs in the registry (See example project).

See HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\PreviewHandlers in the registry.

WindowsPreviewHandlerMBS.DoPreview

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Directs the preview handler to load data from the source specified in an earlier Initialize method call, and to begin rendering to the previewer window.

Lasterror is set.

If the previewer window has not yet been created, then it must be created after this method has been called. The preview handler is responsible for painting the area specified in SetWindow or SetRect. If these methods are called while the preview handler is rendering, the window must be reparented/resized without stopping or restarting the rendering of the item.
This method should be called only after SetWindow has been called.
Additionally, this method should be called only after Constructor has been called.

Some examples using this method:

• /Win/Preview Handler

WindowsPreviewHandlerMBS.InitWithData(data as MemoryBlock)

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Loads the given data.

Lasterror is set.
If loading from data is not supported for preview, we use a temporary file instead.

You need to call Preview next on success to show a preview.

See also:

• InitWithData(data as string)

WindowsPreviewHandlerMBS.InitWithData(data as string)

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Loads the given data.

Lasterror is set.
If loading from data is not supported for preview, we use a temporary file instead.

You need to call Preview next on success to show a preview.

See also:

• InitWithData(data as MemoryBlock)

WindowsPreviewHandlerMBS.InitWithFile(file as folderitem)

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Loads the given file.

Lasterror is set.
If the preview handler does not support reading file, the plugin reads the file and passes as data.

You need to call Preview next on success to show a preview.

If the file path is invalid, the preview will show a file not found error message.

WindowsPreviewHandlerMBS.Unload

Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
method	Windows	MBS Win Plugin	12.3	❌ No	✅ Yes	❌ No	❌ No	Desktop only

Directs the preview handler to cease rendering a preview and to release all resources that have been allocated based on the item passed in during the initialization.

Lasterror is set.
When called, the preview window will be destroyed.

This method should be called only after Constructor has been called. All resources associated with this initialization will be released. Prior to calling DoPreview, this preview handler will be re-initialized with a call to one of the initialization interfaces and a call to SetWindow.