Create DataRelation ship between two tables

There is a simple demo for DataRelation class of DataSet.

while u can use DataTable.Select(conditions) or DataView.Filter to filete the data what you want .however,maybe the method is more complex with this one.

datatalbeperformancetest#regiondatatalbeperformancetest

/**////<summary>
///Testtablerelation.
///</summary>
publicvoidRelation()
...{
DataTabledtParent=this.CreateDataTable();
dtParent.TableName="Parent";

.netframework2.0#region.netframework2.0
DataSetds=newDataSet();
ds.Tables.Add(dtParent);
DataRelationrelations=ds.Relations.Add("Relation",ds.Tables["Parent"].Columns["index"],ds.Tables["Parent"].Columns["parent_index"],false);

foreach(DataRowrowinds.Tables["Parent"].Rows)
#endregion

.netframework1.1#region.netframework1.1
//DataRelationrelations=newDataRelation("Relation",dtParent.Columns["index"],dtParent.Columns["parent_index"],false);
//foreach(DataRowrowindtParent.Rows)
#endregion
...{
if(0!=string.Compare(row["parent_index"].ToString(),"0",true,System.Globalization.CultureInfo.CurrentCulture))
...{
continue;
}

this.DebugPrint(string.Format("{0}",row["description"].ToString()));

this.PrintChilds(row,relations);

this.DebugPrint("--------------------------------------------------");


}
}

/**////<summary>
///printthechild
///</summary>
privatevoidPrintChilds(DataRowrowParent,DataRelationrelations)
...{
DataRow[]rowChilds=rowParent.GetChildRows(relations);

if(null==rowChilds||0==rowChilds.Length)
...{
return;
}

stringspaces=string.Empty;
foreach(DataRowrowinrowChilds)
...{
spaces=spaces.PadLeft(int.Parse(row["layer"].ToString()),' ');
this.DebugPrint(string.Format("{0}|--{1}",spaces,row["description"].ToString()));

this.PrintChilds(row,relations);
}
}

/**////<summary>
///Createthedatatablefortest.
///</summary>
///<returns></returns>
privateDataTableCreateDataTable()
...{
DataTabledt=newDataTable("Test");

//addcolumns
dt.Columns.Add(newDataColumn("index",typeof(Int32)));
dt.Columns.Add(newDataColumn("parent_index",typeof(Int32)));
dt.Columns.Add(newDataColumn("description",typeof(string)));
dt.Columns.Add(newDataColumn("layer",typeof(string)));

//addrows
dt.Rows.Add(newobject[]...{1000,0,"first1",0});
dt.Rows.Add(newobject[]...{1001,1000,"secord2",1});
dt.Rows.Add(newobject[]...{2000,0,"third3",0});
dt.Rows.Add(newobject[]...{2001,1000,"forth4",2});
dt.Rows.Add(newobject[]...{3000,2000,"fifth5",1});
dt.Rows.Add(newobject[]...{3001,3000,"six6",2});
dt.Rows.Add(newobject[]...{2222,0,"seven7",0});


dt.Rows.Add(newobject[]...{100,2222,"first11",1});
dt.Rows.Add(newobject[]...{101,1000,"secord21",1});
dt.Rows.Add(newobject[]...{200,222,"third31",3});
dt.Rows.Add(newobject[]...{201,1001,"forth41",2});
dt.Rows.Add(newobject[]...{300,2000,"fifth51",1});
dt.Rows.Add(newobject[]...{301,3000,"six61",2});
dt.Rows.Add(newobject[]...{222,1000,"seven71",3});

//acceptchanges
dt.AcceptChanges();

//DataSetds=newDataSet("Test");
//ds.Tables.Add(dt);

returndt;
}

privatevoidDebugPrint(stringmsg)
...{
//System.Diagnostics.Debug.WriteLine(msg);
Console.WriteLine(msg);
}
#endregion