Can I pass an instance of a class that I created as the argument in a SendMessage call?
I’ve tried to do it, but keep getting parsing errors that seem to be indicating that it isn’t something that’s going to happen.
Here’s a for instance. Say I have the following in a script on object “Sender”:
class CachedData {
var pos : Vector2;
var isGrabbed : boolean;
}
private var packedData : CachedData();
gameObject.SendMessage("Wakeup", packedData);
… I would think that the following in a script on object “Receiver” would be okay:
class IncomingData {
var pos : Vector2;
var isGrabbed : boolean;
}
private var myData : IncomingData();
function Wakeup (myData : incomingData) {
x = myData.pos;
y = myData.isGrabbed;
}
Thing is, the JS parser seems unhappy with the argument list on the Reciever object’s Wakeup function.
Am I barking up the wrong tree here? Coding it wrong? Or should I just pass an array in the SendMessage call?
I’m not sure, I’ve never done it, however it looks like SendMessage sends an Object.
That means that your receiving function needs to receive an object and then cast it into what it knows it is. It will not implicitly upward cast to an IncomingData object.
Kinda Like this:
function Wakeup (myData : object) {
x = (IncomingData)myData.pos;
y = (IncomingData)myData.isGrabbed;
}
quick written code, you may want to store the casted variable instead of casting multiple times, but hopefully you get the idea.
function SendMessage (methodName : string, value : object = null, options : SendMessageOptions = SendMessageOptions.RequireReceiver) : void
the second parameter is value, and it is an object. object in mono is the base type of all Reference types(classes). You need to send and recieve in the same format, so if SendMessage sends an object whatever you called needs to recieve an object. Once you have it in the form of an object you can cast it to what you know it to be. But you cannot expect SendMessage to figure out on it’s own what you wanted to send and what you expect to be recieved.
If you are at your computer can you tell us what the error line is. It’s incredibly difficult to help remedy a problem when you don’t know what the problem is, but merely the situation that the problem can occur in.
Once you imported System, the code compiler does not know if you want to work with the “Random” class packaged with Unity (Unity - Scripting API: Random) or the “Random” class packaged with the .NET System DLLs (Random Class (System) | Microsoft Learn). Same name, different classes.
So simply, where ever you were using “Random” before, change it to “UnityEngine.Random” (thus telling the compiler exactly which one you want to use)
You need to receive that type.
You could use something that isn’t SendMessage. SendMessage cannot automatically take an object of unknown type, and convert it into a type that it doesn’t know what it is.
I’m sorry I can’t really write an example right now, although if you google you should be able to find C# examples doing similar things (look up boxing and unboxing).
When I use the code above, I don’t get the error I indicated. Actually, I get the following parser error for each of the lines that are trying to recast:
Should I code recasting differently since I am in JS? Using “as” maybe?
function Wakeup (myData : System.Object) {
var data : IncomingData = (IncomingData)myData;
x = data.pos;
y = data.isGrabbed;
}
It does the casting earlier, but it should hopefully work. I’m unsure of casting syntax for javascript as I work in C#, but now that you’ve got the object all you need to do is tell the code that the generic Object that you’ve recieved is actually an IncomingData object. This should do that.
Edit: if ‘myData as IncomingData’ works you could try that as well instead of casting with ().
