Cara menghapus cache ketika aplikasi Anda host kontrol browser web di Visual C#.NET

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Fungsi WinInet

• Penggunaan FindFirstURLCacheEntry fungsi untuk menemukan entri cache pertama.
• Penggunaan FindNextUrlCacheEntry fungsi untuk menghitung melalui cache.
• Penggunaan DeleteUrlCacheEntry fungsi untuk menghapus setiap entri.

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Langkah-langkah untuk menghapus Cache pada Visual C#.NET

1. Mulai Microsoft Visual Studio.NET.
2. Pada File menu, titik Baru, lalu klik Proyek.
3. Dalam Proyek baru kotak dialog, klik Visual C# proyek di bawah Jenis proyek, lalu klik Aplikasi konsol di bawah Template.
4. Kelas Class1.cs, tambahkan kode berikut:

   using System;
   using System.Runtime.InteropServices;
   
   // Visual C# version of Q326201
   namespace Q326201CS
   {
       // Class for deleting the cache.
       class DeleteCache
       {
           // 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);
   
           [STAThread]
           static void Main(string[] args)
           {
               // 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)
               {
                   // 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));		
   
                   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);		
           }
       }
   }
   					

5. Mengkompilasi dan kemudian menjalankan proyek.
6. Untuk mengkonfirmasi bahwa berkas Internet sementara di cache telah dihapus, ikuti langkah-langkah dalam Microsoft Internet Explorer:
   1. Pada Alat menu, klik Opsi Internet.
   2. Dalam Berkas Internet sementara daerah di Umum tab, klik Pengaturan.
   3. Klik Lihat file. Perhatikan bahwa semua file di Internet Explorer cache telah dihapus.

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