ULineBatchComponent’s interface is not exposed to blueprints, and can only be used from C++. There are blueprint wrappers for other methods.
What are you trying to do with it? DrawMesh is used in some debug drawing functions and is not intended for direct use in blueprints.
I am a beginner of UE4.Since this component is called in c++, when is the Cast To LineBatchCompoment Class used in the blueprint?
Note that blueprint arguments can be passed into other C++ functions that you may write.
Thus, the Blueprint system needs to “know” about most of the Unreal classes, even if there is not a lot you can do with them directly in Blueprint.
This means that there’s not a specific decision made as for whether each particular class should or should not be known to Blueprint as a class; it “knows” about all the classes, even if it doesn’t know about a lot of the class properties/methods.
The debug functions that @dmolchanov linked to, end up calling these line batch component methods for you, just not directly on some specific instance.