When I've created an ActorComponent c++ subclass with TSubclassOf UPROPERTY and set this class in blueprint I can't read read this property in c++ constructor.
In .h file I've got this:
protected:
UPROPERTY(EditAnywhere, Category = "Setup")
TSubclassOf<UBaseSkill> PrimarySkillClass;
And this in .cpp:
USkillSet::USkillSet()
{
if(PrimarySkillClass.Get())
{
UE_LOG(LogTemp, Warning, TEXT("Creating skill"));
}
else
{
UE_LOG(LogTemp, Error, TEXT("No skill class"));
}
}
In BP I'm setting a class:
BP screenshot
so PrimarySkillClass.Get() should return true, but I'm getting "No skill class" in log. Why and how could I fix this?
The constructor is the first method ever called on an object, it's to early on the life of the UObject. Properties, values from Blueprints and components are initialized afterwards.
So you have to access them later, either on UObject::PostInitProperties() or on BeginPlay() if it's not too late for your purpose.
Edit: interesting reading on UObject Constructor, PostInitProperties and PostLoad
Related
I've recently been getting into Haxe and just started to use HaxeFlixel to load a Tiled .TMX file.
I am creating a TiledMap object and passing it the TMX file path, then I want to iterate over the layers in that object to add them to the game scene. However when I try to access .tileArray (which is a property of TiledTileLayer) I get the following error :-
flixel.addons.editors.tiled.TiledLayer has no field tileArray
Here is the code:
package;
import flixel.FlxState;
import flixel.tile.FlxTilemap;
import flixel.addons.editors.tiled.TiledMap;
import openfl.Assets;
class PlayState extends FlxState
{
private var _tiled_map:TiledMap;
override public function create():Void
{
_tiled_map = new TiledMap("assets/data/Map1.tmx");
for(layer in _tiled_map.layers){
var layerData:Array<Int> = layer.tileArray;
}
super.create();
}
override public function update(elapsed:Float):Void
{
super.update(elapsed);
}
}
I've found the following example - http://coinflipstudios.com/devblog/?p=182 which seems to work fine for people.
So I wanted to check whether the layer object was a TiledTileLayer as it should be, or TiledLayer, with the following:
trace(Type.typeof(layer));
Which sure enough yields:
PlayState.hx:24: TClass([class TiledTileLayer])
So if it is a TiledTileLayer which has the field tileArray why is it moaning?
I had a look at the source code (https://github.com/HaxeFlixel/flixel-addons/blob/dev/flixel/addons/editors/tiled/TiledMap.hx#L135) and TiledTileLayer inherits from TiledLayer. Layers is an array of type TiledLayer, so I think this is why it is moaning. I can clearly see that the array is storing child objects of TiledLayer, but as soon as I access any props/methods of those children, it complains that the parent does not have that field? Very confusing!
To run I'm using this command: C:\HaxeToolkit\haxe\haxelib.exe run lime test flash -debug -Dfdb
Thank you!
So if it is a TiledTileLayer which has the field tileArray why is it moaning?
It may be a TiledTileLayer in this case, but that may not always be the case. layers is an Array<TileLayer> after all, so it could be a TiledObjectLayer or a TiledImageLayer as well (which don't have a tileArray field). This can nicely be seen in the code you linked. The concrete type can only be known at runtime, but the error you get happens at compile-time.
If you know for sure there won't be any object or image layers, you can just cast it to a TiledTileLayer. However, just to be safe, it's good practice to check the type beforehand anyway:
for (layer in _tiled_map.layers) {
if (Std.is(layer, TiledTileLayer)) {
var tileLayer:TiledTileLayer = cast layer;
var layerData:Array<Int> = tileLayer.tileArray;
}
}
It works without this for the tutorial you linked because it was made for an older version of flixel-addons.
One of the cool new C++ features in Visual Studio 2010 are lambda expressions. However, I can't get them to work within a managed class.
class UnmanagedClass {
void Foo() {
// Creating empty lambda within unmanaged class.
// This compiles fine.
auto lambda = [](){ ; };
}
};
ref class ManagedClass {
void Foo() {
// Creating empty lambda within managed class.
// This creates error C3809:
// A managed type cannot have any friend functions/classes/interfaces.
auto lambda = [](){ ; };
}
};
My best guess is that the compiler creates the anonymous function class as a friend class, even though I never use class members. This seems to mean that lambdas cannot be used at all within ref classes.
I was so happy when I read that VS2010 adds lambda expressions to C++. Does anybody know how to get them to work within ref classes?
Looks like it is being considered for future versions. Otherwise known as: "We'll get to it."
I have just come across an interesting gotcha where optional arguments on an interface and the implementing class can conflict.
I found this out the hard way (school boy error) whilst experimenting. You cannot spot it in the debugger and I assumed it was me messing up the dependency injection.
I'm guessing this is so an alternative interface can give a differing view on what default behaviour should be?
Is there a compiler warning or style cop rule to help point this out?
public interface MyInterface
{
MyStuff Get(bool eagerLoad = true); //this overrules the implementation.
}
public class MyClass : MyInterface
{
public MyStuff Get(bool eagerLoad = false) //will still be true
{
//stuff
}
}
Remember default arguments are a compile-time feature. The compiler picks up the default argument based on the static type of the reference in question and inserts the appropriate default argument. I.e. if you reference is of the interface type you get one behavior but if the reference is of the class type you get the other in your case.
I just received an exception when I try to reference a static variable in another class, which is also statically initialized. This worked before, and for some reason it fails now. The only changes I made were resetting Visual Studio (2010) to its default setting, which I can't imagine to be the reason for this. Any other code I added didn't touch any of the affected parts either.
This is my code
WinForms class 'MainForm':
partial class MainForm : Form
{
// ...
private RefClass convMan;
private Dictionary<EnumType, string> LogNames = RefClass.LogNames;
// ...
public MainForm() { .... }
}
Referenced class 'RefClass':
class RefClass
{
// ...
public enum EnumType { TypeOne = 0, TypeTwo = 1, TypeThree = 2 };
public static Dictionary<EnumType, string> LogNames = new Dictionary<EnumType, string>()
{
{ EnumType.TypeOne, "Text0" },
{ EnumType.TypeTwo, "Text1" },
{ EnumTypy.TypeThree, "Text2" }
};
}
The error I get now is (translated from German):
An unhandled exception of type "System.TypeInitializationException" occurred.
Additional information: The type initializer for "RefClass" threw an exception.
which has the InnerException
System.ArgumentException
So, as far as I'm concerned, my static dictionary should be initialized once it gets accessed, thus when my Form class references it. I tried debugging to see if the static dictionary is initialized before it gets referenced in the Form class, which is not the case. Also, when I stop at a breakpoint for the reference line, the variable LogNames is null.
I'm really confused as to why this happens, it all worked before.
I found my error, the exceptions I got were quite misleading though. It was a problem with a different dictionary than the one I referenced. It probably didn't get initialized in the first place because something before that failed (If someone can clear this up, please feel free to do so!). Basically what I did wrong was using a two-directional dictionary and adding a value twice. This should normally produce a normal exception, but since it was done statically it got wrapped into a TypeInitializationException. I had a deeper look into the exact stacktrace of the inner exception and found where the exception originated from. Maybe this helps someone in the future...
I had a simular issue getting the same exception. Found that my static constructor for my utility class was generating the exception. Took some time locating since the description of the exception was misleading.
As #Yeehaw mentioned, it appears that the exception gets wrapped, so the common denominator here I would say is that the class/object is static.
I have a bit of a complex program which is giving me this apparently phantom error...
I'll start explaining with the help of this little example program I rigged that can throw my beautiful exception for anyone who runs it.
<!-- language: c# -->
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace so_redux {
static class Program {
[STAThread]
static void Main(){
CS2JS _class=new CS2JS();
}
}//class Program
class CS2JS{
public CS2JS(){
Func<String,Object> js_eval=initJS();
Object cs_ic=initCS();
string xc;
object res;
cs_ic.GetType().GetMethod("init").Invoke(cs_ic,null);
AppDomain.CurrentDomain.SetData("trespasser",cs_ic);
xc=#"function edata(fieldname:String,ival:String):Object{
var sob=System.AppDomain.CurrentDomain.GetData('trespasser');
var v1=sob.GetType().GetField(fieldname).GetValue(sob);
function HASH(s1:String,s2:String):Object{
var q1=sob.GetType().GetField(s1).GetValue(sob);
return q1.ITEM(s2);
}
var v2=v1.ITEM(ival);
return eval(v2);
}
edata('HT','foo');";
res=js_eval(xc);
// var xx;xx=new Hashtable();xx['sda']='1';eval(xx['sda']); OK
}
Func<String,Object> initJS(){
System.CodeDom.Compiler.CodeDomProvider jcc;
System.CodeDom.Compiler.CompilerParameters jcp;
System.CodeDom.Compiler.CompilerResults jcr;
System.Reflection.Assembly jas;
object jis;
string code;
Type t_ii;
code=#"#set #debug(off)
import System;
import System.Collections;
import System.Collections.Generic;
package internal_namespace{class internal_class{
public function internal_method(_code:String):Object{
return eval(_code);
}
}
}";
jcc=Microsoft.JScript.JScriptCodeProvider.CreateProvider("JScript");
jcp=new System.CodeDom.Compiler.CompilerParameters();
jcp.CompilerOptions="/fast-";
jcp.GenerateExecutable=false;
jcp.GenerateInMemory=true;
jcp.IncludeDebugInformation=false;
jcp.ReferencedAssemblies.Add("System.dll");
jcp.ReferencedAssemblies.Add("System.Core.dll");
jcp.WarningLevel=4;
jcr=jcc.CompileAssemblyFromSource(jcp,code);
jas=jcr.CompiledAssembly;
jis=jas.CreateInstance("internal_namespace.internal_class");
t_ii=jas.GetType("internal_namespace.internal_class");
return (s1)=>t_ii.InvokeMember("internal_method",System.Reflection.BindingFlags.InvokeMethod,null,jis,new object[]{s1});
}//initJS
Object initCS(){
var v1= Microsoft.CSharp.CSharpCodeProvider.CreateProvider("CSharp");
System.CodeDom.Compiler.CompilerParameters v2=new System.CodeDom.Compiler.CompilerParameters();
v2.GenerateExecutable=false;
v2.GenerateInMemory=true;
v2.IncludeDebugInformation=false;
v2.WarningLevel=4;
v2.ReferencedAssemblies.Add("System.dll");
v2.ReferencedAssemblies.Add("System.Core.dll");
string _code="public Hashtable2 HT;"+
"public void init(){"+
"HT=new Hashtable2();"+
"HT[\"foo\"]=\"1\";"+
"HT[\"bar\"]=\"HASH('HT','foo')\";"+
"}";
var v3="using System;using System.Collections;using System.Collections.Generic;"+
"namespace internal_namespace{public class Hashtable2:Hashtable{"+
"public Hashtable2():base(){} public Hashtable2(int N):base(N){}"+
"public Object ITEM(Object K){return this[K];} }"+
"[Serializable]public class internal_class{"+
"public internal_class(){}"+
_code+
"\n}}";
var v4=v1.CompileAssemblyFromSource(v2,v3);
var v5=v4.CompiledAssembly;
var v6=v5.GetType("internal_namespace.internal_class");
var v7=v5.CreateInstance("internal_namespace.internal_class");
return v7;
}//initCS
}//class CS2JS
}//namespace so_redux
The exception that is thrown is "index out of bounds", and it's thrown from JScript. The problem? It's that there is no array!
What this code is doing: first a JScript interpreter is initialized by compiling at runtime a class that "exports" an eval (one could do a dll, but in this case I didn't).
Then a C# assembly is compiled, an assembly that "exports" some user code (the variable _code in initCS is originally loaded by reading a text file).
After the initialization of the newly compiled class (the invoking of init()), I need the two assemblies (JScript and C#) to interact, so I need to pass data between them, and I thought of using AppDomain.
Note: in the C# assembly an Hashtable2 is defined because I put in there an ITEM method that one can use in alternative to the common property this[]: in this way debugging is easier (for examply by showing a holy MessageBox when accessing the values).
So, I pass the class instantiated in initCS to JScript, and JScript reads the internal Hashtable (HT). What I need to do is evaluate the data in the Hashtable, because it is supposed to be able to alter itself dynamically.
Everything works fine if I eval a string not taken from the Hashtable -- in the moment I take whatever is in the Hashtable and pass it to eval, then exceptions happen. Attention: the strings are absolutely the same (even comparing them with Equals) and they work, the difference is only from where they come from.
When the JScript function edata evals a string taken from the Hashtable, JScript says "index out of bounds", but as I was saying: I don't see any array there... (and maybe the problem is exactly that, dunno).
I admit I have my limitations in JScript, so if anybody could lend a hand to help understand WTF is going on, I would be really happy.
Temporary solution/workaround splitting the JScript function:
xc=#"function odata(fieldname:String,ival:String):Object{
var sob=System.AppDomain.CurrentDomain.GetData('trespasser');
var v1=sob.GetType().GetField(fieldname).GetValue(sob);
return v1.ITEM(ival);
}
odata('HT','bar');";
res=js_eval(xc);
xc=#"function HASH(s1:String,s2:String):Object{
var sob=System.AppDomain.CurrentDomain.GetData('trespasser');
var q1=sob.GetType().GetField(s1).GetValue(sob);
return q1.ITEM(s2);
}
eval("+res.ToString()+");";
res=js_eval(xc);
but if anybody really got any idea of why is wrong in the first example, please explain me!