C# 3.0 Cookbook, 3rd Edition

16.9. Use the Current Internet Connection Settings

Problem

Your program wants to use the current Internet connection settings without forcing the user to add them to your application manually.

Solution

Read the current Internet connectivity settings with the InternetSettingsReader class provided for you in Example 16-7. InternetSettingsReader calls some methods of the WinINet API via P/Invoke to retrieve current Internet connection information. The majority of the work is done in setting up the structures that WinINet uses and then marshaling the structure pointers correctly to retrieve the values.

Example 16-7. InternetSettingsReader class

public class InternetSettingsReader
{
    #region WinInet structures
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct InternetPerConnOptionList
    {
        public int dwSize; // size of the INTERNET_PER_CONN_OPTION_LIST struct
        public IntPtr szConnection;    // Connection name to set/query options
        public int dwOptionCount;    // Number of options to set/query
        public int dwOptionError;        // On error, which option failed
        public IntPtr options;
    };

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct InternetConnectionOption
    {
        static readonly int Size;
        public PerConnOption m_Option;
        public InternetConnectionOptionValue m_Value;
        static Internet ConnectionOption( ) { InternetConnectionOption.Size = Marshal.SizeOf(typeof(InternetConnectionOption)); } // Nested Types [StructLayout(LayoutKind.Explicit)] public struct InternetConnectionOptionValue ...