如何清除缓存，当您的应用程序承载 Visual C#.net 中的 web 浏览器控件
您可能需要以编程方式清除缓存，当您的应用程序承载 web 浏览器控件。但是，此功能不能通过 web 浏览器控件的接口。WinInet 函数
若要清除缓存直接，您可以使用以下 WinInet 函数：
- 使用 FindFirstURLCacheEntry 函数来找到第一个缓存项。
- 枚举通过缓存使用 FindNextUrlCacheEntry 函数。
- 若要删除的每个条目使用 DeleteUrlCacheEntry 函数。
注意： 这些函数只是可用的 Microsoft Internet 浏览器 5。因此，您必须包括相应的检查 （包括这篇文章中的代码示例） 以防止出现错误。
清除缓存 Visual C#.net 中的步骤
在 Visual C#.net 中使用 WinInet 函数，以清除所有在缓存中的文件，请按照下列步骤操作：- 启动 Microsoft Visual Studio.net。
- 在 文件 菜单上指向 新建，然后单击 项目。
- 在 新建项目 对话框中单击在 项目类型，Visual C# 项目，然后单击 模板 下的 控制台应用程序。
- 将下面的代码添加到 Class1.cs 类：
View Code 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);
}
}
}- 编译并运行该项目。
- 要确认已删除 Internet 临时文件缓存中的，请按照 Microsoft Internet Explorer 中的下列步骤操作：
- 在 工具 菜单上单击 Internet 选项。
- 在 常规 选项卡上 临时 Internet 文件 区域中单击 设置。
- 单击 查看文件。请注意所有 Internet Explorer 高速缓存中的文件已被删除。
浙公网安备 33010602011771号