For additional information, see the [COM Callable Wrapper](~/docs/framework/interop/com-callable-wrapper.md), [Runtime Callable Wrapper](~/docs/framework/interop/runtime-callable-wrapper.md), and [Introducing the Class Interface](https://msdn.microsoft.com/library/733c0dd2-12e5-46e6-8de1-39d5b25df024) topics.

For additional information, see the [COM Callable Wrapper](~/docs/framework/interop/com-callable-wrapper.md), [Runtime Callable Wrapper](~/docs/framework/interop/runtime-callable-wrapper.md), and [Introducing the Class Interface](https://msdn.microsoft.com/library/733c0dd2-12e5-46e6-8de1-39d5b25df024) topics.

You can use this method to retrieve slot numbers for members of interfaces that are 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 <xref:System.Runtime.InteropServices.Marshal.GetComSlotForMethodInfo%2A> on a class interface by passing <xref:System.Reflection.MemberInfo> from a class. For additional information, see [Introducing the Class Interface](https://msdn.microsoft.com/library/733c0dd2-12e5-46e6-8de1-39d5b25df024).

This method returns the zero-based, v-table number for an interface or a class. When used on a class, the slot number returned refers to the class interface for the class. If the class interface is auto-dispatch, this method always returns -1 to indicate that the dispatch-only interface does not expose a v-table to managed clients. You can use <xref:System.Runtime.InteropServices.Marshal.GetEndComSlot%2A> and <xref:System.Runtime.InteropServices.Marshal.GetStartComSlot%2A?displayProperty=nameWithType> in conjunction with <xref:System.Runtime.InteropServices.Marshal.GetMethodInfoForComSlot%2A?displayProperty=nameWithType> to pass slots within a specified range. For additional information, see [Introducing the Class Interface](https://msdn.microsoft.com/library/733c0dd2-12e5-46e6-8de1-39d5b25df024).

This method returns the zero-based v-table number for an interface or a class. When used on a class, the slot number that is returned refers to the class interface for the class. If the class interface is auto-dispatch, this method always returns -1 to indicate that the dispatch-only interface does not expose a v-table to managed clients. You can use <xref:System.Runtime.InteropServices.Marshal.GetStartComSlot%2A> and <xref:System.Runtime.InteropServices.Marshal.GetEndComSlot%2A?displayProperty=nameWithType> in conjunction with <xref:System.Runtime.InteropServices.Marshal.GetMethodInfoForComSlot%2A?displayProperty=nameWithType> to pass slots within a specified range. For additional information, see [Introducing the Class Interface](https://msdn.microsoft.com/library/733c0dd2-12e5-46e6-8de1-39d5b25df024).