Question

我有以下两组代码，两者都产生相同的结果：

using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ResetIE
{
    class Program
    {
        [DllImport("InetCpl.cpl", SetLastError=true, CharSet=CharSet.Unicode)]
        public static extern long ClearMyTracksByProcessW(IntPtr hwnd, IntPtr hinst, ref TargetHistory lpszCmdLine, FormWindowState nCmdShow);

    static void Main(string[] args)
    {
        TargetHistory th = TargetHistory.CLEAR_TEMPORARY_INTERNET_FILES;
        ClearMyTracksByProcessW(Process.GetCurrentProcess().Handle, Marshal.GetHINSTANCE(typeof(Program).Module), ref th, FormWindowState.Maximized);
        Console.WriteLine("Done.");
    }
}

和......

static class NativeMethods
{
    [DllImport("kernel32.dll")]
    public static extern IntPtr LoadLibrary(string dllToLoad);

    [DllImport("kernel32.dll")]
    public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);

    [DllImport("kernel32.dll")]
    public static extern bool FreeLibrary(IntPtr hModule);
}

public class CallExternalDLL
{
    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
    public delegate long ClearMyTracksByProcessW(IntPtr hwnd, IntPtr hinst, ref TargetHistory lpszCmdLine, FormWindowState nCmdShow);

    public static void Clear_IE_Cache()
    {
        IntPtr pDll = NativeMethods.LoadLibrary(@"C:\Windows\System32\inetcpl.cpl");
        if (pDll == IntPtr.Zero)
        {
           Console.WriteLine("An Error has Occurred.");
        }

        IntPtr pAddressOfFunctionToCall = NativeMethods.GetProcAddress(pDll, "ClearMyTracksByProcessW");
        if (pAddressOfFunctionToCall == IntPtr.Zero)
        {
            Console.WriteLine("Function Not Found.");
        }

        ClearMyTracksByProcessW cmtbp = (ClearMyTracksByProcessW)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(ClearMyTracksByProcessW));
        TargetHistory q = TargetHistory.CLEAR_TEMPORARY_INTERNET_FILES;
        long result = cmtbp(Process.GetCurrentProcess().Handle, Marshal.GetHINSTANCE(typeof(ClearMyTracksByProcessW).Module), ref q, FormWindowState.Normal);
    }
}

都使用以下枚举：

public enum TargetHistory
{
    CLEAR_ALL = 0xFF,
    CLEAR_ALL_WITH_ADDONS = 0x10FF,
    CLEAR_HISTORY = 0x1,
    CLEAR_COOKIES = 0x2,
    CLEAR_TEMPORARY_INTERNET_FILES = 0x8,
    CLEAR_FORM_DATA = 0x10,
    CLEAR_PASSWORDS = 0x20
}

这两种方法都可以编译并运行得很好，不会出现任何错误，但这两种方法都会无休止地从工作中返回。 PInvoke代码是从以下VB移植的，这很难追踪：

 Option Explicit

Private Enum TargetHistory
    CLEAR_ALL = &HFF&
    CLEAR_ALL_WITH_ADDONS = &H10FF&
    CLEAR_HISTORY = &H1&
    CLEAR_COOKIES = &H2&
    CLEAR_TEMPORARY_INTERNET_FILES = &H8&
    CLEAR_FORM_DATA = &H10&
    CLEAR_PASSWORDS = &H20&
End Enum

Private Declare Function ClearMyTracksByProcessW Lib "InetCpl.cpl" _
   (ByVal hwnd As OLE_HANDLE, _
    ByVal hinst As OLE_HANDLE, _
    ByRef lpszCmdLine As Byte, _
    ByVal nCmdShow As VbAppWinStyle) As Long

Private Sub Command1_Click()
    Dim b() As Byte
    Dim o As OptionButton
    For Each o In Option1
        If o.Value Then
            b = o.Tag
            ClearMyTracksByProcessW Me.hwnd, App.hInstance, b(0), vbNormalFocus
            Exit For
        End If
    Next
End Sub

Private Sub Form_Load()
    Command1.Caption = "削除"

    Option1(0).Caption = "インターネット一時ファイル"
    Option1(0).Tag = CStr(CLEAR_TEMPORARY_INTERNET_FILES)

    Option1(1).Caption = "Cookie"
    Option1(1).Tag = CStr(CLEAR_COOKIES)

    Option1(2).Caption = "履歴"
    Option1(2).Tag = CStr(CLEAR_HISTORY)

    Option1(3).Caption = "フォーム データ"
    Option1(3).Tag = CStr(CLEAR_HISTORY)

    Option1(4).Caption = "パスワード"
    Option1(4).Tag = CStr(CLEAR_PASSWORDS)

    Option1(5).Caption = "すべて削除"
    Option1(5).Tag = CStr(CLEAR_ALL)

    Option1(2).Value = True
End Sub

问题在于我做错了什么？我需要清除互联网缓存，并且更愿意使用这种方法，因为我知道它在我的工作时做了我想要的东西（rundll32 inetcpl.cpl，ClearMyTracksByProcess 8工作正常）。我试过像普通用户和管理员一样运行无济于事。该项目在VS2012中使用C＃编写，并针对.NET3.5编译（由于客户端限制，必须保留为3.5）

Answer 1

rundll32功能的签名是：

void CALLBACK EntryPoint(HWND hwnd, HINSTANCE hinst, LPSTR lpszCmdLine, int nCmdShow);

所以第一个问题是你的第三个参数是一个枚举，它变成一个整数类型，但你需要传递一个字符串。另请注意，这是LPSTR，而不是LPTSTR，因此字符集是ANSI，而不是Unicode。

其次，调用约定是stdcall而不是cdecl。

所以也许更多的内容如下：

[DllImport("InetCpl.cpl", SetLastError = true, CharSet = CharSet.Ansi)]
private static extern void ClearMyTracksByProcess(IntPtr hwnd, IntPtr hinst, string lpszCmdLine, int nCmdShow);

测试哪个在这里工作，至少在获得函数返回时：

class Program
{
    [DllImport("InetCpl.cpl", SetLastError = true, CharSet = CharSet.Ansi)]
    private static extern void ClearMyTracksByProcessW(IntPtr hwnd, IntPtr hinst, string lpszCmdLine, int nCmdShow);

    static void Main(string[] args)
    {
        ClearMyTracksByProcessW(IntPtr.Zero, IntPtr.Zero, "2", 5);
    }
}

如何正确实现inetcpl.cpl作为外部DLL？

1 个答案: