public void CanRemove()
{
DataRelationCollection drcol = _dataset.Relations;
DataColumn parentCol = _dataset.Tables["Customer"].Columns["custid"];
DataColumn childCol = _dataset.Tables["Order"].Columns["custid"];
DataRelation dr = new DataRelation("CustOrder", parentCol, childCol);
drcol.Add(dr);
Assert.True(drcol.CanRemove(dr));
Assert.False(drcol.CanRemove(null));
DataRelation dr2 = new DataRelation("ItemOrder"
, _dataset.Tables["Item"].Columns["itemid"]
, _dataset.Tables["Order"].Columns["custid"]);
Assert.False(drcol.CanRemove(dr2));
}