虚幻引擎4 —类型转换

Question

I am currently developing my first classes in Unreal Engine 4. Coming from using UScript extensively, I'm getting a little bit confused by how typecasting works in pure C++. More specifically, class/object casting.

I am currently putting together a switch statement in MyCustomGameMode which calls upon MyCustomPlayerController for MyCustomPlayerControllerVariable.

The function in question that I am overriding is this one: virtual UClass* GetDefaultPawnClassForController(AController* InController);

Currently I'm trying to call the variable with the following line of code, which I know is incorrect, but I'm not sure why:

Cast<MyCustomPlayerController>(InController).MyCustomPlayerControllerVariable

I am interested in casting the "InController" to MyCustomPlayerController but Cast<MyCustomPlayerController>(InController) doesn't seem to work, what am I doing wrong here?

Answer 1

The cast will return a pointer to your player controller, so you'd need to use -> to dereference it.

const MyCustomPlayerController* MyController = Cast<MyCustomPlayerController>(InController);
check(MyCustomPlayerController);  // asserts that the cast succeeded
const float MyVariable = MyCustomPlayerController->ControllerVariable;

`

Answer 2

When you cast, It always returns a pointer. So make sure you check if the cast is successful before you access variables from a pointer.

auto MyPC = Cast<MyCustomPlayerController>(InController);
if(MyPC)
{
    MyPC->MyVariable;
}