C# disable proxy

I set my webbrowser control's proxy using this function

    private void SetProxy(string proxy)
    {
        INTERNET_PROXY_INFO IPI = new INTERNET_PROXY_INFO();

        IPI.dwAccessType = INTERNET_OPEN_TYPE_PROXY;
        IPI.lpszProxy = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi(proxy);
        IPI.lpszProxyBypass = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi("local");

        IntPtr intptrStruct = System.Runtime.InteropServices.Marshal.AllocCoTaskMem(Sys开发者_如何学JAVAtem.Runtime.InteropServices.Marshal.SizeOf(IPI));


        System.Runtime.InteropServices.Marshal.StructureToPtr(IPI, intptrStruct, true);
        InternetSetOption(IntPtr.Zero, INTERNET_OPTION_PROXY, intptrStruct, System.Runtime.InteropServices.Marshal.SizeOf(IPI));
    }

But I am unable to disable/remove the proxy afterwards, only swap it for another proxy. How can I remove the proxy completely. Already tried by registry.

No plain links as answers.

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Try setting

IPI.dwAccessType to INTERNET_OPEN_TYPE_DIRECT