Ode Data – .NET – Fórum – Programujte.com

Potreboval by som Ode Geom-u nastavit data, co je IntPtr, ako odkaz na nejaku instanciu mojej triedy. Totiz pri nastani kolizie mi to vrati a potreboval by som pouzit, to ako odkaz na tu instanciu z ktorej by som si pobral este nejake parametre. resp. moze to byt aj nejako inac, napr. ze by mi to vratilo hash kod, a pomocou hashtable by som to spravil ale neviem ako.

Tak tedka sem fakt presne nepochopil, co poradne chces.Bud dej nejaky kod nebo to popis "normalne" a vecne.Tenhle popis je fakt na facku.
Akorat k tomu IntPtr => je to vlastne ukazatel na neco.Vetsinou se to pouziva v c++/cli nebo pri psani nejakych wrapperu, ktere vyuzivaji ukazatele. Ten by pak pomoci nejake Marshaling funkce mel jit pretypovat na nejakou tridu.

Napr.:

public class MyObject

{

	string anything;

	IntPtr geom;



	public MyObject(IntPtr colspace)

	{

		geom = Ode.dCreateBox(colspace, 1f, 1f, 1f);

		Ode.dGeomSetData(geom, /* potrebujem tu dostat odkaz na seba */);

	}

}

public class MyLayout

{

	MyObject[] objs1...

	MyObject[] objs2...



	public MyLayout

	{

		// tu sa vytvoria objekty

	}



	protected void OnCollisionCallback(IntPtr data, IntPtr geom1, IntPtr geom2)

	{

		

		anything = (/* potrebujem dostat to data */).anything;

	}

}

Aha, tak takhle moc neporadim. Koukni do nejakeho helpu toho wrapperu na ODE. Jak sem koukal na priklad na strankach ODE pro c++, tak to pretypovaval na ukazatel na tridu.

Tu ti nezbyde asi nic jineho, nez kouknout do documentace nebo se poptat na forech ODE nebo ODE.NET (nebo odkud mas ten wrapper).

a ako sa da IntPtr pretypovat na ukazatela na triedu??

Koukni tady:

http://msdn.microsoft.com/en-us/library/4ca6d5z7.aspx

dajak tomu IntPtr este stale nechapem. ako spravim:

MyObject obj...



IntPtr ptr = /* neco ako dostat sem intptr z obj*/;

((MyObject)/* neco na dostatie to z toho ptr */).anything = ...

IntPtr ptr = (MyObject*)obj;

Pro z obj => IntPtr by melo jit toto:

IntPtr ptr = new IntPtr(obj);

MyObject newObj = (MyObject)Marshal.PtrToStructure(ptr, typeof(MyObject));

Toto mi nejde:

IntPtr ptr = new IntPtr(obj);

[AttributeUsage(AttributeTargets.Class)]

public abstract class MyObject: Attribute

{...



IntPtr ptr = new IntPtr((int)0123456789);

Marshal.StructureToPtr(this, ptr, true);

** ERROR **: Type Engine.GameObject which is passed to unmanaged code must have a StructLayout attribute

aborting...

Stacktrace:



  at (wrapper managed-to-native) System.Runtime.InteropServices.Marshal.StructureToPtr (object,intptr,bool) <0x00004>

  at (wrapper managed-to-native) System.Runtime.InteropServices.Marshal.StructureToPtr (object,intptr,bool) <0xffffffff>

  at...

Pouzil som teraz toto:

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct)]

[StructLayout(LayoutKind.Sequential)]

[ComVisible(true)]

Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object

  at (wrapper unknown) Engine.GameObjectBox:StructureToPtr (object,intptr,bool)

  at (wrapper managed-to-native) System.Runtime.InteropServices.Marshal:StructureToPtr (object,intptr,bool)

  at...

OK, uz to takmer je:
Marshallovat do Ptr mi ide, ale kedze ta trieda obshahuje aj Array nejakej struct, tak mi vypise(pri deMarshallovani):
Structure field of type Draw_Info[] can't be marshalled as LPArray.
A potom este, dalsia vec, ako sa da z Marshallovat System.Type?? lebo ak sa o to pokusim tak mi vypise>

** ERROR **: Type System.Type which is passed to unmanaged code must have a StructLayout attribute

aborting...

Stacktrace:...

public struct OdeData

	{

		public System.Type GOType; // typ obj marshallovaneho, ktora sa pouzije na demarshallovanie GO

		public IntPtr GO; // zmarshallovany obj

	}

Tedka vazne nevim, budes se muset tim progooglovat a prokousat se dokumentaci nebo msdn.

Mi to pripada strasne prekomplikovane, podle me ten wrapper musi mit nejake jednodussi reseni.

alebo asi by to neslo pomocou nejakeho indexu a vsetky objekty(data by bolo int) by som po vytvoreni tam daval, ale co je na to lepsie pouzit?? ja by som pouzil array, ale neni neco lepsie nato??

Mozna struktury by byly lepsi.

myslis, array struktur?? lebo to tak aj chcem, lebo tam budem mat viac veci, alebo namiesto class MyObject pouzit struct??

Ono je to vesmes jedno, protoze muze udelat i pole trid.Zalezi na slozitosti vnitrku (nejake potrebne metody nebo jen property?)

Co je property(som len amater, zatial)??
A metoty to je napr. void xyz()???

EDIT: Aha, nasiel som si to v msdn, oboje tam mam.

Tak pak mas treba lepsi pole trid.Ale jelikoz uz sem se docela solidne ztratil v tom vsem, tak asi vic nebudu schopny pomoct.