S3 Tech Blog: Using the Environment Class

Thursday, July 12, 2007

Using the Environment Class

Environment: .NET, C#

The .NET Framework takes a much different approach to the Environment than Windows. There is a class called Environment, part of the System namespace. The documentation states:

Use this class to retrieve the following information:

Command line arguments
Exit codes
Environment variable settings
Contents of the call stack
Time since last system boot
Version of the common language runtime

Besides getting all or a particular environment variable(s), there are other objects available. Most objects are read only, and there is no method to set or add a variable. As far as I can tell, only CurrentDirectory and ExitCode can be changed. There is no method to add or modify the environment variables. The most interesting thing I noticed when coding the example C# program was the way GetEnvironmentVariables() worked. The method returns an IDictionary object that represents a collection of key-and-value pairs. Another interesting method is GetFolderPath, which retrieves paths to various system folders.

//-----------------------------------------------------------

The following is a C# example of how to retrieve all environment variables.

case 0:
  IDictionary id;
  String sString;

  ArrayList values = new ArrayList();

  m_env_list.Items.Clear ();
  id = Environment.GetEnvironmentVariables();
  foreach (DictionaryEntry myEntry in id)
  {
    sString = myEntry.Key.ToString();
    sString += "=";
    sString += myEntry.Value.ToString();
    m_env_list.Items.Add(sString);
  }
  m_env_list.SetSelected(0, true);
  m_env_list_SelectedIndexChanged(this,null);
  break;
//-----------------------------------------------------------