在 WPF 中你不要这样做

In WPF you don't do this

DataGrid.ItemsSource = DataTable;

相反，你这样做

 DataGrid.ItemsSource = DataTable.AsDataView();

为了取回 DataTable 你可以做这样的事情

In order to get DataTable back you can do something like this

public static DataTable DataViewAsDataTable(DataView dv)
{
    DataTable dt = dv.Table.Clone();
    foreach (DataRowView drv in dv)
       dt.ImportRow(drv.Row);
    return dt;
}

DataView view = (DataView) dataGrid.ItemsSource;
DataTable table = DataViewAsDataTable(view)