Csharp/CSharp Tutorial/Windows/DLL

Call DLL API to move file

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

    class Tester
    {
        [DllImport("kernel32.dll", EntryPoint = "MoveFile",ExactSpelling = false, CharSet = CharSet.Unicode,SetLastError = true)]
        static extern bool MoveFile(string sourceFile, string destinationFile);
        public static void Main()
        {
            ExploreDirectory(new DirectoryInfo("c:\\"));
        }
        private static void ExploreDirectory(DirectoryInfo dir)
        {
            string newDirectory = "newTest";
            DirectoryInfo newSubDir =dir.CreateSubdirectory(newDirectory);
            FileInfo[] filesInDir = dir.GetFiles();
            foreach (FileInfo file in filesInDir)
            {
                string fullName = newSubDir.FullName + "\\" + file.Name;
                file.CopyTo(fullName);
                Console.WriteLine(file.FullName);
            }
            filesInDir = newSubDir.GetFiles();
            int counter = 0;
            foreach (FileInfo file in filesInDir)
            {
                string fullName = file.FullName;
                if (counter++ % 2 == 0)
                {
                    Tester.MoveFile(fullName, fullName + ".bak");
                    Console.WriteLine("{0} renamed to {1}",fullName, file.FullName);
                }else{
                    file.Delete();
                    Console.WriteLine("{0} deleted.",fullName);
                }
            }
            newSubDir.Delete(true);
        }
    }

Compile to dll

// compile with: csc /r:..\logdriver.dll /target:library logaddintofile.cs
using System;
using System.Collections;
using System.IO;
public class LogAddInToFile
{
    StreamWriter streamWriter;
    
    public LogAddInToFile()
    {
        streamWriter = File.CreateText(@"logger.log");
        streamWriter.AutoFlush = true;
    }
    
    public void Log(string message)
    {
        streamWriter.WriteLine(message);
    }
}

Fiber

using System;
using System.Drawing;
using System.Collections;
using System.ruponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;
using System.Threading;
using System.Diagnostics;
public class fmrFibers : System.Windows.Forms.Form {
    private System.Windows.Forms.ListBox lstFibers;
    [DllImport("kernel32.dll")]
    extern static IntPtr ConvertThreadToFiber(int fiberData);
    [DllImport("kernel32.dll")]
    extern static IntPtr CreateFiber(int size, System.Delegate function, int handle);
    [DllImport("kernel32.dll")]
    extern static IntPtr SwitchToFiber(IntPtr fiberAddress);
    [DllImport("kernel32.dll")]
    extern static void DeleteFiber(IntPtr fiberAddress);
    [DllImport("kernel32.dll")]
    extern static int GetLastError();
    delegate void SetTextOutputToEventLog(int number);
    public fmrFibers() {
        this.lstFibers = new System.Windows.Forms.ListBox();
        this.SuspendLayout();
        this.lstFibers.Size = new System.Drawing.Size(320, 212);
        this.ResumeLayout(false);
        Thread t1 = new Thread(new ThreadStart(NewThreadToFiberExecution));
        t1.Start();
    }
    void OutputLog(int fiberNumber) {
        this.Invoke(new AddToListBox(SetText), new object[] { fiberNumber });
        SwitchToFiber(obj);
    }
    void SetText(int message) {
        lstFibers.Items.Add("Fiber " + message.ToString() + " added this");
    }
    delegate void AddToListBox(int message);
    System.IntPtr obj;
    void NewThreadToFiberExecution() {
        try {
            SetTextOutputToEventLog stof = new SetTextOutputToEventLog(OutputLog);
            obj = ConvertThreadToFiber(0);
            long l1 = GetLastError();
            System.IntPtr retVal1 = CreateFiber(500, stof, 1);
            if (GetLastError() != 0) throw new Exception("Create Fiber failed!!");
            IntPtr fiber1return = SwitchToFiber(retVal1);
            if (GetLastError() != 0) throw new Exception("Create Fiber failed!!");
            DeleteFiber(retVal1);
        } catch (Exception e) {
            throw e;
        }
    }
    [STAThread]
    static void Main() {
        Application.Run(new fmrFibers());
    }
}

Invoke MessageBox in Dll

using System;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Text;
    class Program
    {
        [DllImport("user32.dll")]
        public static extern int MessageBox(IntPtr hwnd, String text, String caption, uint type);
        static void Main(string[] args)
        {
            MessageBox(new IntPtr(0), "Greetings from Platform Invoke", "Platform Invoke", 0);
        }
    }

Marshal a function from Dll to a delegate

using System;
using System.Threading;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Text;

    class Program
    {
        [DllImport("kernel32.dll")]
        static extern IntPtr LoadLibrary(string dllName);
        [DllImport("kernel32.dll")]
        static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
        delegate int MessageBoxDelegate(IntPtr hwnd,
            [MarshalAs(UnmanagedType.LPWStr)]string text,
            [MarshalAs(UnmanagedType.LPWStr)]string caption,
            int type);
        static void Main(string[] args)
        {
            IntPtr userApi = LoadLibrary("user32.dll");
            IntPtr msgBoxAddress = GetProcAddress(userApi, "MessageBoxW"); // unicode (wide) message box
            MessageBoxDelegate mbd = (MessageBoxDelegate)Marshal.GetDelegateForFunctionPointer(msgBoxAddress,typeof(MessageBoxDelegate));
            mbd(IntPtr.Zero, "A", "B", 0);
            DoSomething(mbd);
        }
        static void DoSomething(MessageBoxDelegate mbd)
        {
            mbd(IntPtr.Zero, "Work completed.", "Work Progress", 0);
        }
    }

Using load library from Dll

using System;
using System.Threading;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Text;

    class Program
    {
        [DllImport("kernel32.dll")]
        static extern IntPtr LoadLibrary(string dllName);
        [DllImport("kernel32.dll")]
        static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
        delegate int MessageBoxDelegate(IntPtr hwnd,
            [MarshalAs(UnmanagedType.LPWStr)]string text,
            [MarshalAs(UnmanagedType.LPWStr)]string caption,
            int type);
        static void Main(string[] args)
        {
            IntPtr userApi = LoadLibrary("user32.dll");
            IntPtr msgBoxAddress = GetProcAddress(userApi, "MessageBoxW"); // unicode (wide) message box
            MessageBoxDelegate mbd = (MessageBoxDelegate)Marshal.GetDelegateForFunctionPointer(msgBoxAddress,typeof(MessageBoxDelegate));
            mbd(IntPtr.Zero, "A", "B", 0);
            DoSomething(mbd);
        }
        static void DoSomething(MessageBoxDelegate mbd)
        {
            mbd(IntPtr.Zero, "Work completed.", "Work Progress", 0);
        }
    }