Draw Context Is Available Method

public static bool IsAvailable()

Public Shared Function IsAvailable As Boolean

public:
static bool IsAvailable()

static member IsAvailable : unit -> bool 

Return Value

This class can perform drawing operations and access the state of parameters related to drawing only in lock-step with rendering inside of Revit. As a consequence, the facilities of this class are not available for use outside of the scope determined by the callback RenderScene(View, DisplayStyle) . Certain methods of other DirectContext3D objects, e.g., VertexBuffer::Map() are similarly restricted by the same scope.

Reference