NetworkConnection.cs

namespace Tools;

using System.IO;
using System.Runtime.InteropServices;

/// <summary>
/// Wrapper for the "NET USE" functionality.
/// Connect to a network resource, e.g. a network share under a different user.
/// </summary>
/// <remarks>
/// Encapsulate an instance into a using-directive like e.g.:
/// ...
/// using ( new NetworkConnection( @"\\myshare", true, "myUsername", "myPassword" ) )
/// {
///     ...
///     [code that connects to the network share under the new user context]
///     ...
/// }
/// ...
/// </remarks>
[PublicAPI]
public sealed class NetworkConnection : IDisposable
{
    private string? _networkName;

    public NetworkConnection(
        string networkName,
        bool activate,
        string userName,
        string password)
    {
        if (activate)
        {
            doNetUse(networkName, userName, password);
        }
    }

    private void doNetUse(string networkName, string userName, string password)
    {
        var netResource = new NetResource
        {
            Scope = ResourceScope.GlobalNetwork,
            ResourceType = ResourceType.Disk,
            DisplayType = ResourceDisplaytype.Share,
            RemoteName = networkName
        };

        var result = WNetAddConnection2(
            netResource,
            password,
            userName,
            0);

        if (result != 0)
        {
            throw new IOException($"Error connecting to remote share '{networkName}': {result}", result);
        }

        _networkName = networkName;
    }

    ~NetworkConnection()
    {
        doDispose();
    }

    public void Dispose()
    {
        doDispose();
        GC.SuppressFinalize(this);
    }

    private void doDispose()
    {
        if (!string.IsNullOrEmpty(_networkName))
        {
            var nn = _networkName;
            _networkName = null;
            var result = WNetCancelConnection2(nn, 0, true);
            Trace.TraceInformation("Result for canceling network connection: {0}.", result);
        }
    }

    [DllImport(@"mpr.dll", CharSet = CharSet.Unicode)]
    private static extern int WNetAddConnection2(
        NetResource netResource,
        string password,
        string username,
        int flags);

    [DllImport(@"mpr.dll", CharSet = CharSet.Unicode)]
    private static extern int WNetCancelConnection2(
        string? name,
        int flags,
        bool force);
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public class NetResource
{
    // ReSharper disable NotAccessedField.Global
    // ReSharper disable NotAccessedField.Global
    // ReSharper disable UnusedMember.Global
    public ResourceScope Scope;
    public ResourceType ResourceType;
    public ResourceDisplaytype DisplayType;
    public int Usage;
    public string? LocalName;
    public string? RemoteName;
    public string? Comment;
    public string? Provider;
    // ReSharper restore UnusedMember.Global
    // ReSharper restore NotAccessedField.Global
    // ReSharper restore UnusedMember.Global
}

public enum ResourceScope
{
    // ReSharper disable NotAccessedField.Global
    // ReSharper disable UnusedMember.Global
    Connected = 1,
    GlobalNetwork,
    Remembered,
    Recent,
    Context
    // ReSharper restore UnusedMember.Global
    // ReSharper restore UnusedMember.Global
};

public enum ResourceType
{
    // ReSharper disable UnusedMember.Global
    // ReSharper disable UnusedMember.Global
    Any = 0,
    Disk = 1,
    Print = 2,
    Reserved = 8,
    // ReSharper restore UnusedMember.Global
    // ReSharper restore UnusedMember.Global
}

public enum ResourceDisplaytype
{
    // ReSharper disable UnusedMember.Global
    // ReSharper disable UnusedMember.Global
    Generic = 0x0,
    Domain = 0x01,
    Server = 0x02,
    Share = 0x03,
    File = 0x04,
    Group = 0x05,
    Network = 0x06,
    Root = 0x07,
    Shareadmin = 0x08,
    Directory = 0x09,
    Tree = 0x0a,
    Ndscontainer = 0x0b
    // ReSharper restore UnusedMember.Global
    // ReSharper restore UnusedMember.Global
}