SizeOf Method (Object)
Collapse the table of content
Expand the table of content

Marshal.SizeOf Method (Object)

 

Returns the unmanaged size of an object in bytes.

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

<ComVisibleAttribute(True)>
Public Shared Function SizeOf (
	structure As Object
) As Integer

Parameters

structure
Type: System.Object

The object whose size is to be returned.

Return Value

Type: System.Int32

The size of the specified object in unmanaged code.

Exception Condition
ArgumentNullException

The structure parameter is null.

This method accepts an instance of a structure, which can be a reference type or a boxed value type. The layout must be sequential or explicit.

The size returned is the size of the unmanaged object. The unmanaged and managed sizes of an object can differ. For character types, the size is affected by the CharSet value applied to that class.

You can use the SizeOf method to determine how much unmanaged memory to allocate using the AllocHGlobal and AllocCoTaskMem methods.

The following example creates a managed structure, transfers it to unmanaged memory, and then transfers it back to managed memory. This example uses the SizeOf method to determine how much unmanaged memory to allocate.

Imports System
Imports System.Runtime.InteropServices



Public Structure Point
    Public x As Integer
    Public y As Integer
End Structure


Module Example


    Sub Main()

        ' Create a point struct.
        Dim p As Point
        p.x = 1
        p.y = 1

        Console.WriteLine("The value of first point is " + p.x.ToString + " and " + p.y.ToString + ".")

        ' Initialize unmanged memory to hold the struct.
        Dim pnt As IntPtr = Marshal.AllocHGlobal(Marshal.SizeOf(p))

        Try

            ' Copy the struct to unmanaged memory.
            Marshal.StructureToPtr(p, pnt, False)

            ' Create another point.
            Dim anotherP As Point

            ' Set this Point to the value of the 
            ' Point in unmanaged memory. 
            anotherP = CType(Marshal.PtrToStructure(pnt, GetType(Point)), Point)

            Console.WriteLine("The value of new point is " + anotherP.x.ToString + " and " + anotherP.y.ToString + ".")

        Finally
            ' Free the unmanaged memory.
            Marshal.FreeHGlobal(pnt)
        End Try

    End Sub
End Module


Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top
Show:
© 2016 Microsoft