I "borrowed" a class from a CodeProject article related to setting and getting configuration settings. Settings are stored in an XML file and I can set and get name-value pairs (similar to an ini file).
The class is mad up of some static members and static property and some static methods. Something like this:

public class ConfigOpt
{
  private static DataSet dsOptions;
  private static string _ConfigFileName;
  public static string ConfigFileName
  {
    get
      {
  	return _ConfigFileName;
      }
  }

  public static void Initialize(string paraConfigFile)
  {
	_ConfigFileName = paraConfigFile;
	dsOptions = new DataSet("ConfigOpt");

	if (File.Exists(paraConfigFile))
	{
		dsOptions.ReadXml(paraConfigFile);
	}
	else
	{
		DataTable dt = new DataTable("ConfigValues");
		dt.Columns.Add("OptionName", System.Type.GetType("System.String"));
		dt.Columns.Add("OptionValue", System.Type.GetType("System.String"));
		dt.Columns["OptionName"].ColumnMapping = MappingType.Attribute;
		dt.Columns["OptionValue"].ColumnMapping = MappingType.SimpleContent;
		dsOptions.Tables.Add(dt);
	}
  }

  public static void WriteOptions()
  {
	dsOptions.WriteXml(_ConfigFileName, XmlWriteMode.WriteSchema);
  }

  public static string GetOption(string paraOptionName)
  {
	DataView dv = dsOptions.Tables["ConfigValues"].DefaultView;
	dv.RowFilter = "OptionName='" + paraOptionName + "'";

	if (dv.Count > 0)
	{
		return dv[0]["OptionValue"].ToString();
	}
	else
	{
		return "";
	}
  }

  public static void SetOption(string paraOptionName, string paraOptionValue)
  {
	DataView dv = dsOptions.Tables["ConfigValues"].DefaultView;
	dv.RowFilter = "OptionName='" + paraOptionName + "'";
			
	if (dv.Count > 0)
	{
		dv[0]["OptionValue"] = paraOptionValue;
	}
	else
	{
		DataRow dr = dsOptions.Tables["ConfigValues"].NewRow();
		dr["OptionName"] = paraOptionName;
		dr["OptionValue"] = paraOptionValue;
		dsOptions.Tables["ConfigValues"].Rows.Add(dr);
	}
  }
}

I have removed some of the overloads I created. This class works really well, but I am currious to find out more about how a class that has only static members works. Here are some of the questions I have:
1. Is there a penalty to create a class like this compared to creating a class with non-static members where I have to create an instance of the class in order to use it?
2. After I run the Initialize() method how long will the dataset dsOptions be in memory?
3. I added a constructor, with a messagebox telling me that I was in the constructor, to the class. I thought the constructor would be executed the first time a static method in the class was executed, but the constructor was never executed unless I created an instance of the class (but there was no benefit to creating an instance).

Any comments or thoughts about classes with only static members are welcome.

Thanks,
Einar