Проблема кэширования управления WebBrowser

В дополнение к Сержу Сагану, вот код с упрощенной обработкой ошибок, удаленным бесконечным циклом и поддержкой 32/64-бит.

/**
* Modified from code originally found here: http://support.microsoft.com/kb/326201
**/
public class WebBrowserHelper
{
    #region Definitions/DLL Imports
    /// <summary>
    /// For PInvoke: Contains information about an entry in the Internet cache
    /// </summary>
    [StructLayout(LayoutKind.Explicit)]
    public struct ExemptDeltaOrReserverd
    {
        [FieldOffset(0)]
        public UInt32 dwReserved;
        [FieldOffset(0)]
        public UInt32 dwExemptDelta;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct INTERNET_CACHE_ENTRY_INFOA
    {
        public UInt32 dwStructSize;
        public IntPtr lpszSourceUrlName;
        public IntPtr lpszLocalFileName;
        public UInt32 CacheEntryType;
        public UInt32 dwUseCount;
        public UInt32 dwHitRate;
        public UInt32 dwSizeLow;
        public UInt32 dwSizeHigh;
        public FILETIME LastModifiedTime;
        public FILETIME ExpireTime;
        public FILETIME LastAccessTime;
        public FILETIME LastSyncTime;
        public IntPtr lpHeaderInfo;
        public UInt32 dwHeaderInfoSize;
        public IntPtr lpszFileExtension;
        public ExemptDeltaOrReserverd dwExemptDeltaOrReserved;
    }

    // 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

    /// <summary>
    /// Clears the cache of the web browser
    /// </summary>
    public static void ClearCache()
    {
        // Indicates that all of the cache groups in the user's system should be enumerated
        const int CACHEGROUP_SEARCH_ALL = 0x0;
        // Indicates that all the cache entries that are associated with the cache group
        // should be deleted, unless the entry belongs to another cache group.
        const int CACHEGROUP_FLAG_FLUSHURL_ONDELETE = 0x2;
        const int ERROR_INSUFFICIENT_BUFFER = 0x7A;

        // Delete the groups first.
        // Groups may not always exist on the system.
        // For more information, visit the following Microsoft Web site:
        // http://msdn.microsoft.com/library/?url=/workshop/networking/wininet/overview/cache.asp            
        // By default, a URL does not belong to any group. Therefore, that cache may become
        // empty even when the CacheGroup APIs are not used because the existing URL does not belong to any group.            
        long groupId = 0;
        IntPtr enumHandle = FindFirstUrlCacheGroup(0, CACHEGROUP_SEARCH_ALL, IntPtr.Zero, 0, ref groupId, IntPtr.Zero);
        if (enumHandle != IntPtr.Zero) {
            bool more;
            do {
                // Delete a particular Cache Group.
                DeleteUrlCacheGroup(groupId, CACHEGROUP_FLAG_FLUSHURL_ONDELETE, IntPtr.Zero);
                more = FindNextUrlCacheGroup(enumHandle, ref groupId, IntPtr.Zero);
            } while (more);
        }

        // Start to delete URLs that do not belong to any group.
        int cacheEntryInfoBufferSizeInitial = 0;
        FindFirstUrlCacheEntry(null, IntPtr.Zero, ref cacheEntryInfoBufferSizeInitial);  // should always fail because buffer is too small
        if (Marshal.GetLastWin32Error() == ERROR_INSUFFICIENT_BUFFER) {
            int cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
            IntPtr cacheEntryInfoBuffer = Marshal.AllocHGlobal(cacheEntryInfoBufferSize);
            enumHandle = FindFirstUrlCacheEntry(null, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
            if (enumHandle != IntPtr.Zero) {
                bool more;
                do {
                    INTERNET_CACHE_ENTRY_INFOA internetCacheEntry = (INTERNET_CACHE_ENTRY_INFOA)Marshal.PtrToStructure(cacheEntryInfoBuffer, typeof(INTERNET_CACHE_ENTRY_INFOA));
                    cacheEntryInfoBufferSizeInitial = cacheEntryInfoBufferSize;
                    DeleteUrlCacheEntry(internetCacheEntry.lpszSourceUrlName);
                    more = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
                    if (!more && Marshal.GetLastWin32Error() == ERROR_INSUFFICIENT_BUFFER) {
                        cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
                        cacheEntryInfoBuffer = Marshal.ReAllocHGlobal(cacheEntryInfoBuffer, (IntPtr)cacheEntryInfoBufferSize);
                        more = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
                    }
                } while (more);
            }
            Marshal.FreeHGlobal(cacheEntryInfoBuffer);
        }
    }
}

Это расширение ответа Криса Кларка ... этот код слишком важен, я полагаю, что переполнение стека - более безопасное место для его хранения, плюс я избавился от номеров строк для вас. Вот снова ссылка на оригинальную статью: http://www.gutgames.com/post/Clearing-the-Cache-of-a-WebBrowser-Control.aspx

И код:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;

namespace Utilities.Web.WebBrowserHelper
{
    /**
    * Modified from code originally found here: http://support.microsoft.com/kb/326201
    **/
    public class WebBrowserHelper
    {
        #region Definitions/DLL Imports
        /// <summary>
        /// For PInvoke: Contains information about an entry in the Internet cache
        /// </summary>
        [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 System.Runtime.InteropServices.ComTypes.FILETIME LastModifiedTime;
            [FieldOffset(40)]
            public System.Runtime.InteropServices.ComTypes.FILETIME ExpireTime;
            [FieldOffset(48)]
            public System.Runtime.InteropServices.ComTypes.FILETIME LastAccessTime;
            [FieldOffset(56)]
            public System.Runtime.InteropServices.ComTypes.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()
        {
            // Indicates that all of the cache groups in the user's system should be enumerated
            const int CACHEGROUP_SEARCH_ALL = 0x0;
            // Indicates that all the cache entries that are associated with the cache group
            // should be deleted, unless the entry belongs to another cache group.
            const int CACHEGROUP_FLAG_FLUSHURL_ONDELETE = 0x2;
            // File not found.
            const int ERROR_FILE_NOT_FOUND = 0x2;
            // No more items have been found.
            const int ERROR_NO_MORE_ITEMS = 259;
            // Pointer to a GROUPID variable
            long groupId = 0;

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

            // Delete the groups first.
            // Groups may not always exist on the system.
            // For more information, visit the following Microsoft Web site:
            // http://msdn.microsoft.com/library/?url=/workshop/networking/wininet/overview/cache.asp            
            // By default, a URL does not belong to any group. Therefore, that cache may become
            // empty even when the CacheGroup APIs are not used because the existing URL does not belong to any group.            
            enumHandle = FindFirstUrlCacheGroup(0, CACHEGROUP_SEARCH_ALL, IntPtr.Zero, 0, ref groupId, IntPtr.Zero);
            // If there are no items in the Cache, you are finished.
            if (enumHandle != IntPtr.Zero && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                return;

            // Loop through Cache Group, and then delete entries.
            while (true)
            {
                if (ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error() || ERROR_FILE_NOT_FOUND == Marshal.GetLastWin32Error()) { break; }
                // Delete a particular Cache Group.
                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;
            }

            // Start to delete URLs that do not belong to any group.
            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;
                returnValue = DeleteUrlCacheEntry(internetCacheEntry.lpszSourceUrlName);
                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
    }
}

Вескан Петру на правильном пути, я думаю. Очистка кэшей браузера IE довольно трудоемка и не удобна для пользователя. Адаптация предложенного кода MS, связанного Крисом Кларком, для простого удаления конкретного файла из кэша выглядит интересным фрагментом кода для работы, но самым простым ответом было бы получить новое временное имя файла и затем скопировать целевой файл PDF. с этим именем. Затем отобразите временный файл - удалив его при выходе.

Это мое рабочее решение, реализованное, когда я столкнулся с той же проблемой.

Поскольку WebBrowser (на самом деле движок IE Trident) использует WinInet для работы в сети, вы можете использовать API управления кешем WinInet для удаления кэшированных файлов перед перемещением.

Встраивается ли PDF-файл с тегом объекта или чем-то еще? Если это так, запрос на обновление объекта браузера не будет иметь никакого эффекта - вам необходимо создать скрипт для средства просмотра PDF, чтобы выполнить обновление (например, получить объект средства просмотра PDF по идентификатору из элемента управления веб-обозревателя), поскольку это то, что его загрузило. .