== Common C# Libraries ==
=== File and Directory Manipulation ===

  * Create a directory: <code csharp>
using System.IO;
class DirectoryUtil {
    public static void Main() {
        Directory.CreateDirectory("C:\\projdir");
    }
} 
</code>

  * Create subdirectory: <code csharp>
Directory.CreateDirectory("C:\\projdir\\subdir1");
</code>

  * Move a subdirectory: <code csharp>
Directory.Move("C:\\projdir\\subdir", "C:\\projdir2");
</code>

  * Delete directory: <code csharp>
Directory.Delete("C:\\projdir");
</code>

  * Copy or Rename a file: <code csharp>
File.Copy( "c:\\file1.jpg", "c:\\temp\\file2.jpg");
</code>

  * Move a file: <code csharp>
File.Move( "c:\\file1.jpg", "c:\\temp\\file1.jpg");
</code>

  * Delete a file: <code csharp>
File.Delete( "c:\\file1.jpg" );
</code>

  * Check if directory exists: <code csharp>
if (Directory.Exists(folderBrowserDialog1.SelectedPath))
{
    // do something
}
</code>
=== Path Manipulation ===
  * See full list of available ''System.IO.Path'' methods: [[http://msdn.microsoft.com/en-us/library/system.io.path_members.aspx|Path Members]]
  * Get FileName or FilePath (See [[http://msdn.microsoft.com/en-us/library/system.io.path.getfilename.aspx|Path.GetFileName() Method]] or [[http://msdn.microsoft.com/en-us/library/system.io.path.getfilenamewithoutextension.aspx|Path.GetFileNameWithoutExtension() Method]]): <code csharp>
string fileName = @"C:\mydir\myfile.ext";
string path = @"C:\mydir\";
string result;

result = Path.GetFileName(fileName);
Console.WriteLine("GetFileName('{0}') returns '{1}'", 
    fileName, result);

result = Path.GetFileName(path);
Console.WriteLine("GetFileName('{0}') returns '{1}'", 
    path, result);

// This code produces output similar to the following:
//
// GetFileName('C:\mydir\myfile.ext') returns 'myfile.ext'
// GetFileName('C:\mydir\') returns ''
</code>

  * Get file list: <code csharp>
public void GetFileList(dirpath)
{
  DirectoryInfo dir = new DirectoryInfo(dirpath);
  FileInfo[] dirfiles;
  string filemask = "*.jpg";

  if (filemask != "")
  {
      dirfiles = dir.GetFiles(filemask);
  }
  else
  {
      dirfiles = dir.GetFiles();
  }

  foreach(FileInfo f in dirfiles)
  {
      lstImgLibrary.Items.Add(f.Name);
  }
}
</code>

  * Get application startup path: <code csharp>
public string GetAppPath()
{
  return Application.StartupPath;
}
</code>

  * Get temporary path: <code csharp>
string m_Filename = System.IO.Path.GetTempPath() + "\\" + filename;
</code>
            

=== Registry ===

  * Read registry key:<code csharp>
using Microsoft.Win32;
...
RegistryKey hklm = Registry.LocalMachine;
hklm=hklm.OpenSubKey("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0");
Object obp = hklm.GetValue("Identifier");
Console.WriteLine("Processor Identifier :{0}",obp);
</code>

  * Delete registry key: <code csharp>
RegistryKey OurKey = Registry.Users; // Create OurKey set to HKEY_USERS 
OurKey = OurKey.OpenSubKey(".DEFAULT", true ); // Set it to HKEY_USERS\.DEFUALT 
OurKey.CreateSubKey("OurSubKey"); // Create the key HKEY_USERS\.DEAFULT\OurSubKey 
OurKey.CreateSubKey(@"OurSubKey\Subkey"); // Create a sub key HKEY_USERS\.DEFAULT\OurSubKey\Subkey 
OurKey.DeleteSubKey(@"OurSubKey\SubKey"); // Delete the subkey name "subkey" 
OurKey.DeleteSubKeyTree("OurSubKey"); // Delete the whole subkey and any subkeys below it
</code>

  * Other examples: <code csharp>
private string GetNoahModulesPath()
{
    // The name of the key must include a valid root.
    const string userRoot = "HKEY_LOCAL_MACHINE";
    const string subkey = @"\Software\HIMSA\NOAH\Version 3.0\Modules";
    const string keyName = userRoot + subkey;

    return (string)Registry.GetValue(keyName, "DefaultPath", @"C:\Program Files\HIMSA\Modules");
}

private string GetNoahVersion()
{
    // The name of the key must include a valid root.
    const string userRoot = "HKEY_LOCAL_MACHINE";
    const string subkey   = @"\Software\HIMSA\NOAH\Version 3.0";
    const string keyName  = userRoot + subkey;
    string NhVersion      = "0";

    if (Registry.GetValue(keyName, "", "") != null)
    {
        NhVersion = "3.0";
    }
    else
    {
        NhVersion = "0";
    }
    return NhVersion;
}

</code>        

== Graphics ==

=== Screen Capture ===

Source: William Blum, http://www.wblum.org/smallsamp/copyclient.html
<code csharp>
private Bitmap MakeImageOfClient()
{
    Bitmap bm;
    using (Graphics g = CreateGraphics())
    {
        bm = new Bitmap(ClientSize.Width, ClientSize.Height, g);
        using (Graphics h = Graphics.FromImage(bm))
        {
            Point source = PointToScreen(Point.Empty);
            h.CopyFromScreen(source, Point.Empty, ClientSize);
        }
    }
    //bm.Save("C:\tmp\sample.bmp");
    return bm;
}
</code>