void dataGrid2_MouseDoubleClick(object sender, MouseButtonEventArgs e) { var dg = (DataGrid) sender; var item = e.FindDataGridItem<IStatus>(); if (item == null) return; dg.RowDetailsVisibilityMode = dg.RowDetailsVisibilityMode == DataGridRowDetailsVisibilityMode.Collapsed ? DataGridRowDetailsVisibilityMode.Visible : DataGridRowDetailsVisibilityMode.Collapsed; e.Handled = true; }