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Wednesday, February 13, 2013

c# Winforms WebBrowser - Clear all cookies

Hello,
I recently search for a method to delete all cookies from the build in .NET WinForms WebBrowser control.
I didn't found any working solution for it, nor working example.
It being told to use InternetSetOption, but nothing found about it.
So, i will write here my solution for clearing and deleting all cookies.
My solution using InternetSetOption with the option flag: INTERNET_OPTION_SUPPRESS_BEHAVIOR, which described as:

A general purpose option that is used to suppress behaviors on a process-wide basis. The lpBuffer parameter of the function must be a pointer to a DWORD containing the specific behavior to suppress. This option cannot be queried with InternetQueryOption.

This option flag should be used together with INTERNET_SUPPRESS_COOKIE_PERSIST options, which means:

Suppresses the persistence of cookies, even if the server has specified them as persistent.


So the example code for it will be:
static void Main()
{
    SuppressWininetBehavior();

    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

[System.Runtime.InteropServices.DllImport("wininet.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, SetLastError = true)]
public static extern bool InternetSetOption(int hInternet, int dwOption, IntPtr lpBuffer, int dwBufferLength);

private static unsafe void SuppressWininetBehavior()
{
    /* SOURCE: http://msdn.microsoft.com/en-us/library/windows/desktop/aa385328%28v=vs.85%29.aspx
        * INTERNET_OPTION_SUPPRESS_BEHAVIOR (81):
        *      A general purpose option that is used to suppress behaviors on a process-wide basis. 
        *      The lpBuffer parameter of the function must be a pointer to a DWORD containing the specific behavior to suppress. 
        *      This option cannot be queried with InternetQueryOption. 
        *      
        * INTERNET_SUPPRESS_COOKIE_PERSIST (3):
        *      Suppresses the persistence of cookies, even if the server has specified them as persistent.
        *      Version:  Requires Internet Explorer 8.0 or later.
        */

    int option = (int)3/* INTERNET_SUPPRESS_COOKIE_PERSIST*/;
    int* optionPtr = &option;

    bool success = InternetSetOption(0, 81/*INTERNET_OPTION_SUPPRESS_BEHAVIOR*/, new IntPtr(optionPtr), sizeof(int));
    if (!success)
    {
        MessageBox.Show("Something went wrong !>?");
    }
}

Please make sure your project is allows unsafe code. (under Properties => Build Tab)

This code is deleting the COOKIES per PROCESS on startup ONLY.
[tested on WIN-7 and working great]


Best Regards,
MDB-BLOG :)

6 comments:

  1. Another suggestion would be, to delete physically the files on:

    for windows 7:
    %appdata%\Microsoft\Windows\Cookies\
    %appdata%\Microsoft\Windows\Cookies\Low

    for Windows 8:
    %appdata%\Microsoft\Windows\Cookies\INetCookies

    Hope it helps...

    ReplyDelete
  2. thanks a lot :)
    very helpful code

    ReplyDelete
  3. Actually, you don't need an unsafe code. Here is the helper class that works for me:

    public static class WinInetHelper
    {
    public static bool SupressCookiePersist()
    {
    // 3 = INTERNET_SUPPRESS_COOKIE_PERSIST
    // 81 = INTERNET_OPTION_SUPPRESS_BEHAVIOR
    return SetOption(81, 3);
    }

    public static bool EndBrowserSession()
    {
    // 42 = INTERNET_OPTION_END_BROWSER_SESSION
    return SetOption(42, null);
    }

    static bool SetOption(int settingCode, int? option)
    {
    IntPtr optionPtr = IntPtr.Zero;
    int size = 0;
    if (option.HasValue)
    {
    size = sizeof (int);
    optionPtr = Marshal.AllocCoTaskMem(size);
    Marshal.WriteInt32(optionPtr, option.Value);
    }

    bool success = InternetSetOption(0, settingCode, optionPtr, size);

    if (optionPtr != IntPtr.Zero) Marshal.Release(optionPtr);
    return success;
    }

    [DllImport("wininet.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool InternetSetOption(
    int hInternet,
    int dwOption,
    IntPtr lpBuffer,
    int dwBufferLength
    );
    }

    You call SupressCookiePersist somewhere at the start of the process and
    EndBrowserSession to clear cookies when browser is closed as described here:
    http://stackoverflow.com/questions/23206199/facebook-multi-account

    ReplyDelete