EnumUnknown.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / MS / Internal / Controls / EnumUnknown.cs / 1305600 / EnumUnknown.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
//
// Description: Helper object implementing IEnumUnknown for enumerating controls 
// 
//              Source copied from AxContainer.cs
// 
// History
//  04/17/05    KusumaV      Created
//
//----------------------------------------------------------------------------- 

using System; 
using System.Collections; 
using System.Diagnostics;
using System.Runtime.InteropServices; 
using Microsoft.Win32;
using System.Security;

using MS.Win32; 

namespace MS.Internal.Controls 
{ 
    #region class EnumUnknown
 
    internal class EnumUnknown : UnsafeNativeMethods.IEnumUnknown
    {
        private Object[] arr;
        private int loc; 
        private int size;
 
        internal EnumUnknown(Object[] arr) 
        {
            this.arr = arr; 
            this.loc = 0;
            this.size = (arr == null) ? 0 : arr.Length;
        }
 
        private EnumUnknown(Object[] arr, int loc)
            : this(arr) 
        { 
            this.loc = loc;
        } 

        ///
        ///     Critical: Takes arbitrary pointers, writes to memory
        /// 
        [SecurityCritical]
        unsafe int UnsafeNativeMethods.IEnumUnknown.Next(int celt, IntPtr rgelt, IntPtr pceltFetched) 
        { 
            if (pceltFetched != IntPtr.Zero)
                Marshal.WriteInt32(pceltFetched, 0, 0); 

            if (celt < 0)
            {
                return NativeMethods.E_INVALIDARG; 
            }
 
            int fetched = 0; 
            if (this.loc >= this.size)
            { 
                fetched = 0;
            }
            else
            { 
                for (; this.loc < this.size && fetched < celt; ++(this.loc))
                { 
                    if (this.arr[this.loc] != null) 
                    {
                        Marshal.WriteIntPtr(rgelt, Marshal.GetIUnknownForObject(this.arr[this.loc])); 
                        rgelt = (IntPtr)((long)rgelt + (long)sizeof(IntPtr));
                        ++fetched;
                    }
                } 
            }
 
            if (pceltFetched != IntPtr.Zero) 
                Marshal.WriteInt32(pceltFetched, 0, fetched);
 
            if (fetched != celt)
            {
                return (NativeMethods.S_FALSE);
            } 
            return NativeMethods.S_OK;
        } 
 
        int UnsafeNativeMethods.IEnumUnknown.Skip(int celt)
        { 
            this.loc += celt;
            if (this.loc >= this.size)
            {
                return (NativeMethods.S_FALSE); 
            }
            return NativeMethods.S_OK; 
        } 

        void UnsafeNativeMethods.IEnumUnknown.Reset() 
        {
            this.loc = 0;
        }
 
        void UnsafeNativeMethods.IEnumUnknown.Clone(out UnsafeNativeMethods.IEnumUnknown ppenum)
        { 
            ppenum = new EnumUnknown(this.arr, this.loc); 
        }
    } 
    #endregion class EnumUnknown
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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