Csharp/C Sharp/Windows/Windows API

BitBlt

 
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public class Form1 : Form {
    const int SRCCOPY = 0xcc0020;
    [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]
    private static extern int BitBlt(
      IntPtr hdcDest,     // handle to destination DC (device context)
      int nXDest,         // x-coord of destination upper-left corner
      int nYDest,         // y-coord of destination upper-left corner
      int nWidth,         // width of destination rectangle
      int nHeight,        // height of destination rectangle
      IntPtr hdcSrc,      // handle to source DC
      int nXSrc,          // x-coordinate of source upper-left corner
      int nYSrc,          // y-coordinate of source upper-left corner
      System.Int32 dwRop  // raster operation code
      );
    public Form1() {
        InitializeComponent();
    }
    private void Form1_Paint(object sender, PaintEventArgs e) {
        Graphics g = e.Graphics;
        g.FillRectangle(Brushes.White, ClientRectangle);
        g.DrawRectangle(Pens.Black, 10, 10, 40, 40);
        IntPtr dc = g.GetHdc();
        BitBlt(dc, 70, 0, 60, 60, dc, 0, 0, SRCCOPY);
        g.ReleaseHdc(dc);
    }
    private void InitializeComponent() {
        this.SuspendLayout();
        this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 16F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 268);
        this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
        this.ResumeLayout(false);
    }
    [STAThread]
    static void Main() {
        Application.EnableVisualStyles();
        Application.Run(new Form1());
    }
}

DLL: GetVersionEx

 
using System;
using System.Runtime.InteropServices;
[StructLayout(LayoutKind.Sequential)]
class OSVersionInfo {
    public int dwOSVersionInfoSize;
    public int dwMajorVersion;
    public int dwMinorVersion;
    public int dwBuildNumber;
    public int dwPlatformId;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
    public String szCSDVersion;
}
class MainClass {
    [DllImport("kernel32.dll")]
    public static extern bool GetVersionEx([In, Out] OSVersionInfo osvi);
    static void Main(string[] args) {
        OSVersionInfo osvi = new OSVersionInfo();
        osvi.dwOSVersionInfoSize = Marshal.SizeOf(osvi);
        GetVersionEx(osvi);
        Console.WriteLine("Class size: " + osvi.dwOSVersionInfoSize);
        Console.WriteLine("Major Version: " + osvi.dwMajorVersion);
        Console.WriteLine("Minor Version: " + osvi.dwMinorVersion);
        Console.WriteLine("Build Number: " + osvi.dwBuildNumber);
        Console.WriteLine("Platform Id: " + osvi.dwPlatformId);
        Console.WriteLine("CSD Version: " + osvi.szCSDVersion);
        Console.WriteLine("Platform: " + Environment.OSVersion.Platform);
        Console.WriteLine("Version: " + Environment.OSVersion.Version);
    }
}

Get OS Version from kernel32.dll

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        API.OSVERSIONINFO info = new API.OSVERSIONINFO();
        info.dwOSVersionInfoSize = Marshal.SizeOf(info);
        bool resp = API.GetVersionEx(ref info);
        if (resp == false) {
            Console.WriteLine("GetVersion failed");
        }
        Console.WriteLine("{0}.{1}.{2}",
            info.dwMajorVersion,
            info.dwMinorVersion,
            info.dwBuildNumber);
    }
}
public class API {
    [DllImport("kernel32.dll")]
    public static extern
        bool GetVersionEx(ref OSVERSIONINFO lpVersionInfo);
    [StructLayout(LayoutKind.Sequential)]
    public struct OSVERSIONINFO {
        public System.Int32 dwOSVersionInfoSize;
        public System.Int32 dwMajorVersion;
        public System.Int32 dwMinorVersion;
        public System.Int32 dwBuildNumber;
        public System.Int32 dwPlatformId;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
        public String szCSDVersion;
    }
}

Get the Total Free Space on a Drive by using kernel32.dll

 
using System;
using System.Runtime.InteropServices;
public class GetFreeSpace {
    [DllImport("kernel32.dll", EntryPoint="GetDiskFreeSpaceExA" )]
    private static extern long GetDiskFreeSpaceEx(string lpDirectoryName, out long lpFreeBytesAvailableToCaller, out long lpTotalNumberOfBytes, out long lpTotalNumberOfFreeBytes);
    private static void Main() {
        long result, total, free, available;
        result = GetDiskFreeSpaceEx("c:", out available, out total, out free);
        if (result != 0) {
            Console.WriteLine("Total Bytes: {0:N}", total);
            Console.WriteLine("Free Bytes: {0:N}", free);
            Console.WriteLine("Available Bytes: {0:N}", available);
        }
    }
}

import CreateDirectory and FormatMessage

 
using System;
using System.Text;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        bool resp = API.CreateDirectory(@"c*:\file.txt", IntPtr.Zero);
        if (resp == false) {
            StringBuilder message;
            int errorcode = Marshal.GetLastWin32Error();
            API.FormatMessage(API.FORMAT_MESSAGE_ALLOCATE_BUFFER | API.FORMAT_MESSAGE_FROM_SYSTEM | API.FORMAT_MESSAGE_IGNORE_INSERTS,IntPtr.Zero, errorcode,0, out message, 0, IntPtr.Zero);
            Console.WriteLine(message);
        }
    }
}
public class API {
    [DllImport("kernel32.dll", SetLastError = true)]
    public static extern bool CreateDirectory(string lpPathName, IntPtr lpSecurityAttributes);
    [DllImport("kernel32.dll", SetLastError = false)]
    public static extern System.Int32 FormatMessage(
        System.Int32 dwFlags,
        IntPtr lpSource,
        System.Int32 dwMessageId,
        System.Int32 dwLanguageId,
        out StringBuilder lpBuffer,
        System.Int32 nSize,
        IntPtr va_list);
    public const int FORMAT_MESSAGE_ALLOCATE_BUFFER = 256;
    public const int FORMAT_MESSAGE_IGNORE_INSERTS = 512;
    public const int FORMAT_MESSAGE_FROM_STRING = 1024;
    public const int FORMAT_MESSAGE_FROM_HMODULE = 2048;
    public const int FORMAT_MESSAGE_FROM_SYSTEM = 4096;
    public const int FORMAT_MESSAGE_ARGUMENT_ARRAY = 8192;
    public const int FORMAT_MESSAGE_MAX_WIDTH_MASK = 255;
}

imports the GetModuleHandleW function specifically

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        int hProcess = API.GetModuleHandleW(null);
    }
}
public class API {
    [DllImport("kernel32.dll", ExactSpelling = true)]
    public static extern int GetModuleHandleW(string filename);
}

imports the printf function

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        int val1 = 5, val2 = 10;
        API.printf("%d+%d=%d", val1, val2, val1 + val2);
    }
}
public class API {
    [DllImport("msvcrt.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
    public static extern int printf(string formatspecifier, int lhs, int rhs, int total);
}

imports three functions to display the vertical and horizontal size of the screen.

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        IntPtr hDC = API.GetDC(IntPtr.Zero);
        int v = API.GetDeviceCaps(hDC, API.HORZRES);
        Console.WriteLine("Vertical size of window {0}mm.", v);
        int h = API.GetDeviceCaps(hDC, API.HORZRES);
        Console.WriteLine("Horizontal size of window {0}mm.", h);
        int resp = API.ReleaseDC(IntPtr.Zero, hDC);
        if (resp != 1) {
            Console.WriteLine("Error releasing hdc");
        }
    }
}
public static class API {
    [DllImport("user32.dll")]
    public static extern IntPtr GetDC(IntPtr hWnd);
    [DllImport("user32.dll")]
    public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
    [DllImport("gdi32.dll")]
    public static extern int GetDeviceCaps(IntPtr hDC, int nIndex);
    public const int HORZSIZE = 4;  // horizontal size in pixels
    public const int VERTSIZE = 6;  // vertical size in pixels
    public const int HORZRES = 8;   // horizontal size in millimeters
    public const int VERTRES = 10;  // vertical size in millimeters
}

Keyboard timer: GetTickCount

 
using System;
using System.Drawing;
using System.Collections;
using System.ruponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;
public class KeyTimer : System.Windows.Forms.Form {
    private System.ruponentModel.Container components = null;
    private uint start = 0;
    private uint stop = 0;
    [DllImport("kernel32.dll")]
    public static extern uint GetTickCount();
    public KeyTimer() {
    }
    [STAThread]
    static void Main() {
        Application.Run(new KeyTimer());
    }
    protected override void OnKeyDown(KeyEventArgs args) {
        start = GetTickCount();
    }
    protected override void OnKeyUp(KeyEventArgs args) {
        stop = GetTickCount();
        uint elapsed = (stop - start);
        MessageBox.Show(Convert.ToString(args.KeyData) + ", time elapsed: " + Convert.ToString(elapsed) + " msecs");
    }
}

marshals string for unmanaged memory as ANSI.

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        int hProcess = API.GetModuleHandle(null);
    }
}
public class API {
    [DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
    public static extern int GetModuleHandle(string filename);
}

MessageBox from user32.dll

 
using System;
using System.Runtime.InteropServices;
public class Starter {
    public static void Main() {
        string caption = "Visual C# 2005";
        string text = "Hello, world!";
        API.ShowMessage(0, text, caption, 0);
    }
}
public class API {
    [DllImport("user32.dll", EntryPoint = "MessageBox")]
    public static extern int ShowMessage(int hWnd,
        string text, string caption, uint type);
}