Builds up the filter for a file dialog.

FileDialogFilter.cs

public class FileDialogFilter
{
	private readonly string _filter;
	private readonly string _description;

	public string Description
	{
		get { return _description; }
	}

	public string Filter
	{
		get { return _filter; }
	}

	public FileDialogFilter(string description, string filter)
	{
		_description = description;
		_filter = filter;
	}

	public static string From(params string[] values)
	{
		if (values.Length % 2 == 1)
		{
			throw new ArgumentException(@"Must have a matching filter for each description", "values");
		}

		var filters = new FileDialogFilter[values.Length / 2];

		for (var i = 0; i < filters.Length; i++)
		{
			filters[i] = new FileDialogFilter(values[2 * i], values[2 * i + 1]);
		}

		return filters.Build();
	}

	public override string ToString()
	{
		return string.Format("{0} ({1})|{1}", Description, Filter);
	}
}

public static class FileDialogFilterExtensions
{
	public static string Build(this IList<FileDialogFilter> filters)
	{
		return string.Join("|", filters);
	}
}