public FilterElementEditorViewModel(FilterBase filter = null) { if (filter != null) { this._currentSelectedItem = filter.Identifier + ": " + filter.Description; this._prevDescString = this._currentSelectedItem; ConfiguredFilterBase = QueryCompiler.ToFilter(filter.ToQuery()).Filters.First() as FilterBase; this.IsNegate = filter.Negate; } else { this.CurrentSelectedItem = GetFilterDescriptions().First(); } this._filterDescriptions = GetFilterDescriptions().ToArray(); }