private void EditFileAssociation(object sender, EventArgs e) { FileAssociation selection = GetSelectedFileAssociation(); if (selection == null) { return; } OpenEditor((FileAssociation)selection.Clone(), form => { selection.CopyFrom(form.FileAssociation); mySettings.SetIndexedValue(myLambdaExpression, myFileAssociations.Where(pair => pair.Value == selection).Select(_ => _.Key).First(), selection); }); }