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C Implementation of Cleaning IE Browser Cache

  • 2021-07-24 11:43:18
  • OfStack

This article illustrates the C # implementation of clearing the IE browser cache. Share it for your reference. The details are as follows:

Several problems of wpf webbrowser encountered in the project, which are recorded under 1 here

1. Handling of bind event for jquery in webbrowser.

There is no problem with this writing under ordinary browser 1 


 　　 var content = $("<div><h4><span>" + category_name + "</span>(<a id='href_" + guid + "' href='AddOrEditShowInfo.aspx?Category=" + guid + "'> Add Presentation </a>)" +
  "<span id='edit_" + guid + "' style='font-size:12px;cursor:pointer;' onclick='showCategory(this, \""+guid+"\")'> Modify classification </span>&nbsp;&nbsp;" +
  "<span id='del_" + guid + "' style='font-size:12px;cursor:pointer;' onclick=delCategory(this, \""+guid+"\")'> Delete classification </span></h4>" +
  "<table class='gridview' cellspacing='0' rules='all' border='1' id='gvData' width='100%'>" +
  "<thead><tr><th> Thumbnail </th><th> Presentation name </th><th> Brief introduction </th><th> Detailed description </th><th> Operation </th></tr></thead>" +
  "<tbody id='t_" + guid + "' class='css_tbody'></tbody></table></div>"
);
$("#vtab").append(content);

However, in webbrowser, the event will not respond, so remove onclick from content and bind it as follows: 


$("#edit_" + guid).unbind("click").bind("click", function () { showCategory(this, guid) });
$("#del_" + guid).unbind("click").bind("click", function () { delCategory(this,guid)});

2. Problems with jquery uploadify upload components in webbrowser

When using this component, it is found that when uploading pictures, there is no problem when uploading them for the first time, and there is no problem when uploading them for the second time. There is no reaction, no error, no progress of uploading, and the background code uploaded cannot be triggered.

The solution is to clear the browser cache and Ok. Here's how the code empties the cache

3. Ways to clean up the IE cache

Obviously, IE's cache in its directory does not show the location of the real file, the file location is in a hidden folder, and this hidden folder we can't find. Several ways to empty the cache on the Internet, here I 11 show the code and the effect of processing. For your reference.

Use the ie cache path to delete the cached 


string cachePath = Environment.GetFolderPath(Environment.SpecialFolder.InternetCache);
// Get the cache path 
DirectoryInfo di = new DirectoryInfo(cachePath);
foreach (FileInfo fi in di.GetFiles("*.*", SearchOption.AllDirectories))// Traverse all folders   Delete the files inside 
{
  try
  {
   fi.Delete();
  }
  catch { }
}

Effect: The cache file is not actually deleted. And there are many exceptions, such as enguser. dat, index. dat, etc. When these files are deleted, there will be an error that another program is still using.

Call winnet. dll to clean up the code on the cache 


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Rntime.InteropServices;
using System.IO;
namespace WpfClient.AppCode
{
 public class ClearCache
 {
  [StructLayout(LayoutKind.Explicit, Size = 80,CharSet=CharSet.Auto)]
  protected 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)]
  protected 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)]
  protected 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)]
  protected 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)]
  protected 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)]
  protected 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)]
  protected static extern bool DeleteUrlCacheEntry(
   IntPtr lpszUrlName)
  public static void DelCache(){
   // 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);
    string s = Marshal.PtrToStringAnsi(internetCacheEntry.lpszLocalFileName);
    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);  
  }
 }
}

Effect: Generally speaking, it is still a little effective, but the efficiency is extremely low, and there will be long waiting conditions and program suspended animation. The most important thing is that I don't know when it will end.

③ Call RunDll32.exe 


RunCmd("RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 8");
void RunCmd(string cmd)
{
 System.Diagnostics.Process p = new System.Diagnostics.Process();
 p.StartInfo.FileName = "cmd.exe";
 //  Shut down Shell Use of 
 p.StartInfo.UseShellExecute = false;
 //  Redirect standard input 
 p.StartInfo.RedirectStandardInput = true;
 //  Redirect standard output 
 p.StartInfo.RedirectStandardOutput = true;
 // Redirect error output 
 p.StartInfo.RedirectStandardError = true;
 p.StartInfo.CreateNoWindow = true;
 p.Start();
 p.StandardInput.WriteLine(cmd);
 p.StandardInput.WriteLine("exit");
}

Effect: This method solves my problem, and the cache is emptied.

The following is a description of the other parameters: 


//Temporary Internet Files  ( Internet Temporary file) 
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 8
//Cookies
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 2
//History ( Historical record )
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 1
//Form Data  (Form data) 
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 16
//Passwords ( Password) 
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 32
//Delete All  (Delete All) 
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 255
//Delete All - "Also delete files and settings stored by add-ons"
//RunDll32.exe InetCpl.cpl,ClearMyTracksByProcess 4351

I hope this article is helpful to everyone's C # programming.

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