For C# Interop, how to deal with pointer field in struct in IDL?

[Lawrence Li via .NET 247]

How to deal with pointer field in struct in idl So that C# can call C++ COM?

e.g.

in C++ COM Server IDL:
typedef struct
{
long *xPos;
long yPos;
} MYPOINT;
...
...
interface IIDraw : IUnknown
{
HRESULT DrawALine([in,out] MYPOINT* p1, [in,out] MYPOINT* p2);
};

in C# Client:
// We want to remove the * (pointer) of xPos.
// The class will become:
public class MYPOINT
{
public long xPos;
public long yPos;
};

// When calling the COM function:
MYPOINT pt1, pt2;
draw.DrawALine(ref pt1, ref pt2);


How to make this kind of implementation?
Is it required to modify the IL Assembler file for certain marshaling? If yes, how?

 

[BuddyWork]

Checkout IntPtr see the following link
http://msdn.microsoft.com/library/default.asp?
url=/library/en-
us/cpref/html/frlrfSystemIntPtrClassTopic.asp

-----Original Message-----
How to deal with pointer field in struct in idl So that C# can call C++ COM?

e.g.

in C++ COM Server IDL:
typedef struct
{
long *xPos;
long yPos;
} MYPOINT;
...
...
interface IIDraw : IUnknown
{
HRESULT DrawALine([in,out] MYPOINT* p1, [in,out] MYPOINT* p2);
};

in C# Client:
// We want to remove the * (pointer) of xPos.
// The class will become:
public class MYPOINT
{
public long xPos;
public long yPos;
};

// When calling the COM function:
MYPOINT pt1, pt2;
draw.DrawALine(ref pt1, ref pt2);


How to make this kind of implementation?
Is it required to modify the IL Assembler file for

certain marshaling? If yes, how?

 

[lawrence]

We want to avoid IntPtr because it is dangerous to use pointer in C#.

Checkout IntPtr see the following link
http://msdn.microsoft.com/library/default.asp?
url=/library/en-
us/cpref/html/frlrfSystemIntPtrClassTopic.asp

-----Original Message-----
How to deal with pointer field in struct in idl So that C# can call C++ COM?

e.g.

in C++ COM Server IDL:
typedef struct
{
long *xPos;
long yPos;
} MYPOINT;
...
...
interface IIDraw : IUnknown
{
HRESULT DrawALine([in,out] MYPOINT* p1, [in,out] MYPOINT* p2);
};

in C# Client:
// We want to remove the * (pointer) of xPos.
// The class will become:
public class MYPOINT
{
public long xPos;
public long yPos;
};

// When calling the COM function:
MYPOINT pt1, pt2;
draw.DrawALine(ref pt1, ref pt2);


How to make this kind of implementation?
Is it required to modify the IL Assembler file for

certain marshaling? If yes, how?

--------------------------------
From: Lawrence Li

-----------------------
Posted by a user from .NET 247 (http://www.dotnet247.com/)

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