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Marshal.PtrToStructure Method (IntPtr, Type)

Marshals data from an unmanaged block of memory to a newly allocated managed object of the specified type.

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

'Declaration
<ComVisibleAttribute(True)> _
Public Shared Function PtrToStructure ( _
	ptr As IntPtr, _
	structureType As Type _
) As Object

Parameters

ptr
Type: System.IntPtr
A pointer to an unmanaged block of memory.
structureType
Type: System.Type
The type of object to be created. This object must represent a formatted class or a structure.

Return Value

Type: System.Object
A managed object containing the data pointed to by the ptr parameter.

ExceptionCondition
ArgumentException

The structureType parameter layout is not sequential or explicit.

-or-

The structureType parameter is a generic type.

ArgumentNullException

structureType is Nothing.

PtrToStructure is often necessary in COM interop and platform invoke when structure parameters are represented as an System.IntPtr value. You can pass a value type to this overload method. In this case, the returned object is a boxed instance.

The following example creates a managed structure, transfers it to unmanaged memory, and then transfers it back to managed memory using the PtrToStructure method.


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




The following example demonstrates how to marshal an unmanaged block of memory to a managed structure using the PtrToStructure method.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

  • SecurityCriticalAttribute 

    requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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