public void AddRange()
{
DataRelationCollection drcol = _dataset.Relations;
DataRelation dr1 = new DataRelation("CustOrder"
, _dataset.Tables["Customer"].Columns["custid"]
, _dataset.Tables["Order"].Columns["custid"]);
DataRelation dr2 = new DataRelation("ItemOrder"
, _dataset.Tables["Item"].Columns["itemid"]
, _dataset.Tables["Order"].Columns["custid"]);
drcol.AddRange(new DataRelation[] { dr1, dr2 });
Assert.Equal("CustOrder", drcol[0].RelationName);
Assert.Equal("ItemOrder", drcol[1].RelationName);
}