在BindingSource对象中分配dataMember属性时出现问题

Question

我有一种情况，例如我有3张桌子

如果我有链接到其他两个表（UnitGroup和UnitGroupDetail）的Unit表

如何正确创建其BindingSources

我写了一个我想做的事的例子。我把里面的一切都弄清楚了

请帮助我

这是代码：

private BindingSource _mainBs;
private BindingSource _unitGroupBs;
private BindingSource _unitGroupDetailBs;

private BindingSource _unitUnitGroupBs;
private BindingSource _unitUnitGroupDetail;

private static DataSet GetDataSet()
{
    var dataSet = new DataSet("UnitGroup");

    // Create unit table that contains units informations 
    var unit = new DataTable("Unit");
    unit.Columns.Add(new DataColumn("UnitID", typeof(int)));
    unit.Columns.Add(new DataColumn("UnitName", typeof(string)));
    dataSet.Tables.Add(unit);

    // Create Unit group 
    var unitGroup = new DataTable("UnitGroup");
    unitGroup.Columns.Add(new DataColumn("GroupID", typeof(int)));
    unitGroup.Columns.Add(new DataColumn("GroupName", typeof(string)));
    unitGroup.Columns.Add(new DataColumn("BaseUnitID", typeof(int)));
    dataSet.Tables.Add(unitGroup);
    // Adding the relation between UnitGroup table and Unit table

    var unitGroupDetail = new DataTable("UnitGroupDetail");
    unitGroupDetail.Columns.Add(new DataColumn("UnitGroupDetailID", typeof(int)));
    unitGroupDetail.Columns.Add(new DataColumn("UnitGroupID", typeof(int)));
    unitGroupDetail.Columns.Add(new DataColumn("UnitID", typeof(int)));
    unitGroupDetail.Columns.Add(new DataColumn("ConversionRate", typeof(decimal)));
    dataSet.Tables.Add(unitGroupDetail);

    // Relation Name : Unit:UnitGroup
    dataSet.Relations.Add("Unit:UnitGroup",unit.Columns["UnitID"], unitGroup.Columns["BaseUnitID"]);
    // Relation Name : UnitGroup:UnitGroupDetail
    dataSet.Relations.Add("UnitGroup:UnitGroupDetail",unitGroup.Columns["GroupID"], unitGroupDetail.Columns["UnitGroupID"]);
    // Relation Name : Unit:UnitGroupDetail
    dataSet.Relations.Add("Unit:UnitGroupDetail",unit.Columns["UnitID"], unitGroupDetail.Columns["UnitID"]);

    return dataSet;
}


private void PrepareBindingSources()
{
    _mainBs = new BindingSource(GetDataSet(), string.Empty);

    _unitGroupBs = new BindingSource(_mainBs, "UnitGroup");

    _unitGroupDetailBs = new BindingSource(_unitGroupBs, "UnitGroup:UnitGroupDetail");

    _unitUnitGroupBs = new BindingSource(_unitGroupBs, "Unit:UnitGroup");

    _unitUnitGroupDetail = new BindingSource(_unitGroupDetailBs, "Unit:UnitGroupDetail");

}


private void Form1_Load(object sender, EventArgs e)
{
    PrepareBindingSources();
}

当我运行代码时，它说System.ArgumentException：在数据源上找不到'DataMember属性'Unit：UnitGroup'。'