John Terenece

My suggestion is to replace the GeDialog variable by a pointer and be sure that the allocation and the deletion is done in the mainthread.

Because the GeDialog was not initialised correctly, the CDIalog was not defined so the function dlg.IsOpen() was crashing.
For extra check, you can check CDialog against nullptr like so

CDialog* intern = dlg->Get();

I also change the TRUE to true. TRUE should be avoided.

#include "c4d_general.h"
#include "c4d.h"
#include "c4d_symbols.h"

#include "maxon/thread.h"

#define ID_RUNDIALOG 1059364
 

enum Controls
{
	idSendMessageLinkObject = 1000,
	idLinkedObject,
	idGatherChildren,

	idOverallScrollGroup = 2000,
	idGroupToFlush,
	idControls,

	idLaunchDialogWindow = 1500,
	idBasicControlGroup,
};

class ObjDialog : public GeDialog
{
public:
	virtual Bool CreateLayout();
	virtual Bool InitValues();
	virtual void DestroyWindow();
	virtual Bool Command(Int32 id, const BaseContainer& msg);
	virtual Int32 Message(const BaseContainer& msg, BaseContainer& result);
};


Bool ObjDialog::CreateLayout()
{
	Bool res = GeDialog::CreateLayout();
	SetTitle("Dialog Window"_s);
	ScrollGroupBegin(idOverallScrollGroup, BFH_SCALEFIT | BFV_SCALEFIT, SCROLLGROUP_VERT | SCROLLGROUP_HORIZ);
	{
		GroupBegin(idGroupToFlush, BFH_SCALEFIT | BFV_SCALEFIT, 1, 0, String(), 0);
		{
			GroupBegin(idControls, BFH_SCALEFIT | BFV_SCALEFIT, 5, 0, String(), 0);
			{
			}
			GroupEnd();
		}
		GroupEnd();
	}
	GroupEnd();

	return res;
}

Bool ObjDialog::InitValues()
{
	if (!GeDialog::InitValues())
		return false;
	return true;
}

void ObjDialog::DestroyWindow() {}

Bool ObjDialog::Command(Int32 id, const BaseContainer& msg)
{
	return true;
}


Int32 ObjDialog::Message(const BaseContainer& msg, BaseContainer& result)
{
	return GeDialog::Message(msg, result);
}




class RunDialog : public ObjectData
{
public:
	virtual Bool Init(GeListNode* node);

	virtual BaseObject* GetVirtualObjects(BaseObject* op, HierarchyHelp* hh);
	virtual Bool Message(GeListNode* node, Int32 type, void* t_data);
	virtual Bool GetDDescription(GeListNode* node, Description* description, DESCFLAGS_DESC& flags);

	static NodeData* Alloc() { return NewObjClear(RunDialog); }

	maxon::BaseArray<BaseObject*> objArrayToCheckForMatch;

	void Free(GeListNode* node) override;
private:
	ObjDialog *dlg = nullptr;


};

Bool RunDialog::Init(GeListNode* node)
{
	if (dlg == nullptr)
	{
		maxon::ExecuteOnMainThread([this]() 
			{
				dlg = NewObjClear(ObjDialog);
			});
	}
	
	return true;
}

void RunDialog::Free(GeListNode* node) 
{
	if (dlg)
	{
		maxon::ExecuteOnMainThread([this]()
			{
				DeleteObj(dlg);
				dlg = nullptr;
			});
	}
}

Bool RunDialog::GetDDescription(GeListNode* node, Description* description, DESCFLAGS_DESC& flags)
{
	BaseContainer* dataInstance;
	const DescID* singleid;
	if (!description->LoadDescription(node->GetType()))
	{
	}

	dataInstance = ((BaseList2D*)node)->GetDataInstance(); // Get the container for the tag
	if (!dataInstance)
		return FALSE;
	singleid = description->GetSingleDescID();
	DescID cid;


	DescID DescHelperControlGroup = DescLevel(idBasicControlGroup, DTYPE_GROUP, 0);
	if (!singleid || DescHelperControlGroup.IsPartOf(*singleid, NULL))
	{
		BaseContainer bc;
		bc = GetCustomDataTypeDefault(DTYPE_GROUP);
		bc.SetString(DESC_NAME, "Run Dialog"_s);
		bc.SetInt32(DESC_COLUMNS, 1);
		bc.SetInt32(DESC_DEFAULT, 1);
		bc.SetBool(DESC_SCALEH, true);

		if (!description->SetParameter(DescHelperControlGroup, bc, DescLevel(ID_RUNDIALOG)))
			return true;
	}


	cid = DescLevel(idLaunchDialogWindow, DTYPE_BUTTON, 0);
	if (!singleid || cid.IsPartOf(*singleid, NULL))  //  important to check for speedup c4d!
	{
		BaseContainer bc;
		bc = GetCustomDataTypeDefault(DTYPE_BUTTON);
		bc.SetInt32(DESC_CUSTOMGUI, CUSTOMGUI_BUTTON);
		bc.SetString(DESC_NAME, "Open Dialog"_s);
		if (!description->SetParameter(cid, bc, DescHelperControlGroup))
			return true;
	}




	flags |= DESCFLAGS_DESC::LOADED;

	return true;
}




Bool RunDialog::Message(GeListNode* node, Int32 type, void* t_data)
{
	if (type == MSG_DESCRIPTION_COMMAND)
	{
		DescriptionCommand* dc = (DescriptionCommand*)t_data;
		if (!dc)
			return true;
		Int32 ID = Int32(dc->_descId[0].id);
		BaseDocument* doc = node->GetDocument();
		if (!doc)
			return true;

		switch (ID)
		{
			// Problem occurs here
			case idLaunchDialogWindow:
			{
				if (dlg)
				{
					CDialog* intern = dlg->Get();
					if (intern)
					{
						if (dlg->IsOpen() == false)
							dlg->Open(DLG_TYPE::ASYNC, ID_RUNDIALOG, -1, -1, 300, 200, 0, OPENDIALOGFLAGS::IGNORELAYOUT);
					}
				}
				break;
			}
		}
	}

	return true;
}

BaseObject* RunDialog::GetVirtualObjects(BaseObject* op, HierarchyHelp* hh)
{
	BaseObject* nullReturn = BaseObject::Alloc(Onull);

	return nullReturn;
}
Bool RegisterRunDialog();
Bool RegisterRunDialog()
{

	return RegisterObjectPlugin(ID_RUNDIALOG, "Run Dialog"_s, OBJECT_GENERATOR | OBJECT_INPUT, RunDialog::Alloc, ""_s, AutoBitmap("atom.tif"_s), 0);
}

Cheers,
Manuel

I was able to reproduce the issue. I need to ask ours devs the best way to fix this.

Cheers,
Manuel

Cheers
Manuel