using System;
using System.Runtime.InteropServices;

namespace MyClass
{
    
    static class WebBrowserHelper
    {
        #region Definitions/DLL Imports
        // For PInvoke: Contains information about an entry in the Internet cache
        [StructLayout(LayoutKind.Explicit, Size = 80)]
        public struct INTERNET_CACHE_ENTRY_INFOA
        {
            [FieldOffset(0)]
            public uint dwStructSize;
            [FieldOffset(4)]
            public IntPtr lpszSourceUrlName;
            [FieldOffset(8)]
            public IntPtr lpszLocalFileName;
            [FieldOffset(12)]
            public uint CacheEntryType;
            [FieldOffset(16)]
            public uint dwUseCount;
            [FieldOffset(20)]
            public uint dwHitRate;
            [FieldOffset(24)]
            public uint dwSizeLow;
            [FieldOffset(28)]
            public uint dwSizeHigh;
            [FieldOffset(32)]
            public FILETIME LastModifiedTime;
            [FieldOffset(40)]
            public FILETIME ExpireTime;
            [FieldOffset(48)]
            public FILETIME LastAccessTime;
            [FieldOffset(56)]
            public FILETIME LastSyncTime;
            [FieldOffset(64)]
            public IntPtr lpHeaderInfo;
            [FieldOffset(68)]
            public uint dwHeaderInfoSize;
            [FieldOffset(72)]
            public IntPtr lpszFileExtension;
            [FieldOffset(76)]
            public uint dwReserved;
            [FieldOffset(76)]
            public uint dwExemptDelta;
        }

        // For PInvoke: Initiates the enumeration of the cache groups in the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindFirstUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr FindFirstUrlCacheGroup(
            int dwFlags,
            int dwFilter,
            IntPtr lpSearchCondition,
            int dwSearchCondition,
            ref long lpGroupId,
            IntPtr lpReserved);

        // For PInvoke: Retrieves the next cache group in a cache group enumeration
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindNextUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool FindNextUrlCacheGroup(
            IntPtr hFind,
            ref long lpGroupId,
            IntPtr lpReserved);

        // For PInvoke: Releases the specified GROUPID and any associated state in the cache index file
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "DeleteUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool DeleteUrlCacheGroup(
            long GroupId,
            int dwFlags,
            IntPtr lpReserved);

        // For PInvoke: Begins the enumeration of the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindFirstUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr FindFirstUrlCacheEntry(
            [MarshalAs(UnmanagedType.LPTStr)] string lpszUrlSearchPattern,
            IntPtr lpFirstCacheEntryInfo,
            ref int lpdwFirstCacheEntryInfoBufferSize);

        // For PInvoke: Retrieves the next entry in the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindNextUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool FindNextUrlCacheEntry(
            IntPtr hFind,
            IntPtr lpNextCacheEntryInfo,
            ref int lpdwNextCacheEntryInfoBufferSize);

        // For PInvoke: Removes the file that is associated with the source name from the cache, if the file exists
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "DeleteUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool DeleteUrlCacheEntry(
            IntPtr lpszUrlName);
        #endregion

        #region Public Static Functions
        /// <summary>
        /// Clears the cache of the web browser
        /// </summary>
        public static void ClearCache()
        {
            
            const int CACHEGROUP_SEARCH_ALL = 0x0;
                      
            const int CACHEGROUP_FLAG_FLUSHURL_ONDELETE = 0x2;
            
            const int ERROR_FILE_NOT_FOUND = 0x2;
           
            const int ERROR_NO_MORE_ITEMS = 259;
            
            long groupId = 0;

            
            int cacheEntryInfoBufferSizeInitial = 0;
            int cacheEntryInfoBufferSize = 0;
            IntPtr cacheEntryInfoBuffer = IntPtr.Zero;
            INTERNET_CACHE_ENTRY_INFOA internetCacheEntry;
            IntPtr enumHandle = IntPtr.Zero;
            bool returnValue = false;

            
            enumHandle = FindFirstUrlCacheGroup(0, CACHEGROUP_SEARCH_ALL, IntPtr.Zero, 0, ref groupId, IntPtr.Zero);
           
            if (enumHandle != IntPtr.Zero && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                return;

            
            while (true)
            {
                if (ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error() || ERROR_FILE_NOT_FOUND == Marshal.GetLastWin32Error()) { break; }
                
                returnValue = DeleteUrlCacheGroup(groupId, CACHEGROUP_FLAG_FLUSHURL_ONDELETE, IntPtr.Zero);
                if (!returnValue && ERROR_FILE_NOT_FOUND == Marshal.GetLastWin32Error())
                {
                    returnValue = FindNextUrlCacheGroup(enumHandle, ref groupId, IntPtr.Zero);
                }

                if (!returnValue && (ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error() || ERROR_FILE_NOT_FOUND == Marshal.GetLastWin32Error()))
                    break;
            }

            
            enumHandle = FindFirstUrlCacheEntry(null, IntPtr.Zero, ref cacheEntryInfoBufferSizeInitial);
            if (enumHandle != IntPtr.Zero && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                return;

            cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
            cacheEntryInfoBuffer = Marshal.AllocHGlobal(cacheEntryInfoBufferSize);
            enumHandle = FindFirstUrlCacheEntry(null, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);

            while (true)
            {
                internetCacheEntry = (INTERNET_CACHE_ENTRY_INFOA)Marshal.PtrToStructure(cacheEntryInfoBuffer, typeof(INTERNET_CACHE_ENTRY_INFOA));
                if (ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error()) { break; }

                cacheEntryInfoBufferSizeInitial = cacheEntryInfoBufferSize;

                //我自己加的Try Catch=.=,不然按一按就當了
                try
                {
                    returnValue = DeleteUrlCacheEntry(internetCacheEntry.lpszSourceUrlName);
                }
                catch
                {
                    break;
                }


                if (!returnValue)
                {
                    returnValue = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
                }
                if (!returnValue && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                {
                    break;
                }
                if (!returnValue && cacheEntryInfoBufferSizeInitial > cacheEntryInfoBufferSize)
                {
                    cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
                    cacheEntryInfoBuffer = Marshal.ReAllocHGlobal(cacheEntryInfoBuffer, (IntPtr)cacheEntryInfoBufferSize);
                    returnValue = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
                }
            }
            Marshal.FreeHGlobal(cacheEntryInfoBuffer);
        }
        #endregion
    }
}

welkingunther 發表在 痞客邦 PIXNET 留言(0) 人氣()