Marshal.GetComSlotForMethodInfo Method

Gets the virtual function table (VTBL) slot for a specified System.Reflection.MemberInfo when exposed to COM.

Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)

public static int GetComSlotForMethodInfo (
	MemberInfo m
public static int GetComSlotForMethodInfo (
	MemberInfo m
public static function GetComSlotForMethodInfo (
	m : MemberInfo
) : int
Not applicable.



A MemberInfo that represents an interface method.

Return Value

The VTBL (also called v-table) slot m identifier when it is exposed to COM.

Exception typeCondition


The m parameter is a null reference (Nothing in Visual Basic).


The m parameter is not a MethodInfo object.


The m parameter is not an interface method.

The zero-based slot number returned by this method accounts for three IUnknown and possibly four IDispatch methods, making the value of the first available slot either 3 or 7. GetComSlotForMethodInfo provides the opposite functionality of Marshal.GetMethodInfoForComSlot.

You can use this method to retrieve slot numbers for members of interfaces not visible from COM and for members of private interfaces. The slot numbers returned correspond to the v-table numbers that would be reserved if the type was exposed to COM. COM-invisible members actually occupy a slot in an exposed v-table, even though the COM client cannot use the slot. You cannot use GetComSlotForMethodInfo on a class interface by passing MemberInfo from a class. For additional information on class interfaces, see Introducing the Class Interface.


This method uses SecurityAction.LinkDemand to prevent it from being called from untrusted code; only the immediate caller is required to have SecurityPermissionAttribute.UnmanagedCode permission. If your code can be called from partially trusted code, do not pass user input to Marshal class methods without validation. For important limitations on using the LinkDemand member, see Demand vs. LinkDemand.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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