public string InitialLocation {get; set;}

/// Adds a single item to a map
OpenItemDialog addToMapDialog = new OpenItemDialog()
{
  Title = "Add To Map",
  InitialLocation = @"C:\Data\NewYork\Counties\Erie\Streets",
  Filter = ItemFilters.Composite_AddToMap
};

SaveItemDialog saveLayerFileDialog = new SaveItemDialog()
{
  Title = "Save Layer File",
  InitialLocation = @"C:\Data\ProLayers\Geographic\Streets",
  Filter = ItemFilters.Files_All
};