Csharp/C Sharp/Language Basics/DLL Library

Calling Native DLL Functions

/*
A Programmer"s Introduction to C# (Second Edition)
by Eric Gunnerson
Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 31 - Interop\Calling Native DLL Functions
// copyright 2000 Eric Gunnerson
using System.Runtime.InteropServices;
public class CallingNativeDLLFunctions
{
    [DllImport("user32.dll")]
    public static extern int MessageBox(int h, string m, 
    string c, int type);
    public static void Main()
    {
        int retval = MessageBox(0, "Hello", "Caption", 0);
    }
}

Creates a library assembly

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/

/*
  Example16_2.cs creates a library assembly
*/
// compile with: csc /target:library Example16_2.cs
using System;
using System.Reflection;
using System.Windows.Forms;
[assembly:AssemblyVersionAttribute("1.0.0.0")]
[assembly:AssemblyTitleAttribute("Example 16.2")]
public class Example16_2 
{
  string privateString;
  public string inString 
  {
    get 
    {
      return privateString;
    }
    set
    {
      privateString = inString;
    }
  }
  public void upper(out string upperString)
  {
    upperString = privateString.ToUpper();
  }
}

File to be used as a library assembly

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa
Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//  Circle.cs -- File to be used as a library assembly
//
//               Compile this file with the following command line:
//                   C:>csc /t:library Circle.cs
using System;
namespace nsCircle
{
// A structure to define a Cartesian point.
    public struct POINT
    {
        public POINT (int x, int y)
        {
            cx = x;
            cy = y;
        }
        public int  cx;
        public int  cy;
        public override string ToString()
        {
           return (String.Format ("(" + cx + ", " + cy + ")"));
        }
    }
    public class clsCircle
    {
// Two constructors to define the circle.
        public clsCircle (double radius, POINT center)
        {
            m_Center = center;
            m_Radius = radius;
        }
        public clsCircle (double radius, int cx, int cy)
        {
            m_Center.cx = cx;
            m_Center.cy = cy;
            m_Radius = radius;
        }
        public clsCircle ()
        {
            m_Center.cx = 0;
            m_Center.cy = 0;
            m_Radius = 0;
        }
        public double Radius
        {
            get {return (m_Radius);}
            set {m_Radius = value;}
        }
        public POINT Center
        {
            get {return (m_Center);}
            set {m_Center = value;}
        }
// Fields to contain circle data.
        POINT m_Center;
        private double m_Radius;
// Constants to make life easier
        private const double pi = 3.14159;
        private const double radian = 57.29578;
// Return the area of the circle
        public double Area
        {
            get {return (m_Radius * m_Radius * pi);}
        }
// Return the diameter of the circle
        public double Diameter
        {
            get {return (2 * m_Radius);}
        }
// Return the coordinates of a point on the circle at a given angle.
        public POINT PointOnCircle (double degrees)
        {
            POINT pt;
            double fAngle = degrees / radian;
// Compute the x position of the point
            pt.cx = (int)((double) m_Radius * Math.Cos (fAngle) + 0.5);
// Compute the y position of the point
            pt.cy = (int)((double) m_Radius * Math.Sin (fAngle) + 0.5);
            return (pt);
        }
// Return the area of a slice determined by a given angle.
        public double AreaOfSlice (double degrees)
        {
            double fAngle = degrees / 57.29578;
            return (Area * fAngle / (2 * pi));
        }
    }
}

// Geom.cs -- Demonstrates using an assembly.
//
//            Compile this program with the following command line:
//                C:>csc /r:circle.dll Geom.cs
using System;
using nsCircle;
namespace nsGeometry
{
    class clsMain
    {
        static public void Main ()
        {
            double angle = 32.6;
// Create an instance of the circle class.
            clsCircle circle = new clsCircle (420, 0, 0);
// Get the point on the circle at the angle.
            POINT pt = circle.PointOnCircle (angle);
// Show the total area of the circle.
            Console.WriteLine ("The area of the circle is " + circle.Area);
// Show the point.
            Console.WriteLine ("The point on the circle is at " + pt);
// Show the area of the slice between 0 degrees and the angle.
            Console.WriteLine ("The area of the slice is " +
                                circle.AreaOfSlice (angle));
        }
    }
}

File to be used as a library assembly 2

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa
Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//  Circle.cs -- File to be used as a library assembly
//
//               Compile this file with the following command line:
//                   C:>csc /t:module Circle.cs
using System;
namespace nsCircle
{
// A structure to define a Cartesian point.
    public struct POINT
    {
        public POINT (int x, int y)
        {
            cx = x;
            cy = y;
        }
        public int  cx;
        public int  cy;
        public override string ToString()
        {
           return (String.Format ("(" + cx + ", " + cy + ")"));
        }
    }
    public class clsCircle
    {
// Two constructors to define the circle.
        public clsCircle (double radius, POINT center)
        {
            m_Center = center;
            m_Radius = radius;
        }
        public clsCircle (double radius, int cx, int cy)
        {
            m_Center.cx = cx;
            m_Center.cy = cy;
            m_Radius = radius;
        }
        public clsCircle ()
        {
            m_Center.cx = 0;
            m_Center.cy = 0;
            m_Radius = 0;
        }
        public double Radius
        {
            get {return (m_Radius);}
            set {m_Radius = value;}
        }
        public POINT Center
        {
            get {return (m_Center);}
            set {m_Center = value;}
        }
// Fields to contain circle data.
        POINT m_Center;
        private double m_Radius;
// Constants to make life easier
        private const double pi = 3.14159;
        private const double radian = 57.29578;
// Return the area of the circle
        public double Area
        {
            get {return (m_Radius * m_Radius * pi);}
        }
// Return the diameter of the circle
        public double Diameter
        {
            get {return (2 * m_Radius);}
        }
// Return the coordinates of a point on the circle at a given angle.
        public POINT PointOnCircle (double degrees)
        {
            POINT pt;
            double fAngle = degrees / radian;
// Compute the x position of the point
            pt.cx = (int)((double) m_Radius * Math.Cos (fAngle) + 0.5);
// Compute the y position of the point
            pt.cy = (int)((double) m_Radius * Math.Sin (fAngle) + 0.5);
            return (pt);
        }
// Return the area of a slice determined by a given angle.
        public double AreaOfSlice (double degrees)
        {
            double fAngle = degrees / 57.29578;
            return (Area * fAngle / (2 * pi));
        }
    }
}

// Geom.cs -- Demonstrates using an assembly.
//
//            Build this program and the Circle assembly using
//            the following command sequence:
//                C:>csc /t:module Circle.cs
//                C:>sn -k Circle.snk
//                C:>al /keyfile:Circle.snk /version:1.0.0.0 /out:Circle.dll Circle.NetModule
//                C:>gacutil /i Circle.dll
//                C:>csc /r:circle.dll Geom.cs
//
using System;
using nsCircle;
namespace nsGeometry
{
    class clsMain
    {
        static public void Main ()
        {
            double angle = 32.6;
// Create an instance of the circle class.
            clsCircle circle = new clsCircle (420, 0, 0);
// Get the point on the circle at the angle.
            POINT pt = circle.PointOnCircle (angle);
// Show the total area of the circle.
            Console.WriteLine ("The area of the circle is " + circle.Area);
// Show the point.
            Console.WriteLine ("The point on the circle is at " + pt);
// Show the area of the slice between 0 degrees and the angle.
            Console.WriteLine ("The area of the slice is " +
                                circle.AreaOfSlice (angle));
        }
    }
}

Loading Assemblies: Making it Dynamic

/*
A Programmer"s Introduction to C# (Second Edition)
by Eric Gunnerson
Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 30 - Execution-Time Code Generation\Loading Assemblies\Making it Dynamic
// copyright 2000 Eric Gunnerson
// file=LogAddInToFile.cs
// compile with: csc /r:..\logdriver.dll /target:library logaddintofile.cs
using System;
using System.Collections;
using System.IO;
public class LogAddInToFile: ILogger
{
    StreamWriter streamWriter;
    
    public LogAddInToFile()
    {
        streamWriter = File.CreateText(@"logger.log");
        streamWriter.AutoFlush = true;
    }
    
    public void Log(string message)
    {
        streamWriter.WriteLine(message);
    }
}
//=============================================================
// 30 - Execution-Time Code Generation\Loading Assemblies
// copyright 2000 Eric Gunnerson
// file=LogDriver.cs
// compile with: csc /target:library LogDriver.cs
using System;
using System.Collections;
public interface ILogger
{
    void Log(string message);
}
public class LogDriver
{
    ArrayList loggers = new ArrayList();
    
    public LogDriver()
    {
    }
    
    public void AddLogger(ILogger logger)
    {
        loggers.Add(logger);
    }
    
    public void Log(string message) 
    {
        foreach (ILogger logger in loggers)
        {
            logger.Log(message);
        }
    }
}
public class LogConsole: ILogger
{
    public void Log(string message)
    {
        Console.WriteLine(message);
    }
}