ChildViews y relaciones (ADO.NET)
Actualización: November 2007
Si existe una relación entre tablas de un DataSet, puede crear una DataView que contenga filas de la tabla secundaria relacionada mediante el método CreateChildView de la DataRowView para las filas de la tabla primaria. Por ejemplo, en el código siguiente se muestran Categories y los Products relacionados en orden alfabético por CategoryName y ProductName.
Dim catTable As DataTable = catDS.Tables("Categories")
Dim prodTable As DataTable = catDS.Tables("Products")
' Create a relation between the Categories and Products tables.
Dim relation As DataRelation = catDS.Relations.Add("CatProdRel", _
catTable.Columns("CategoryID"), _
prodTable.Columns("CategoryID"))
' Create DataViews for the Categories and Products tables.
Dim catView As DataView = New DataView(catTable, "", _
"CategoryName", DataViewRowState.CurrentRows)
Dim prodView As DataView
' Iterate through the Categories table.
Dim catDRV, prodDRV As DataRowView
For Each catDRV In catView
Console.WriteLine(catDRV("CategoryName"))
' Create a DataView of the child product records.
prodView = catDRV.CreateChildView(relation)
prodView.Sort = "ProductName"
For Each prodDRV In prodView
Console.WriteLine(vbTab & prodDRV("ProductName"))
Next
Next
DataTable catTable = catDS.Tables["Categories"];
DataTable prodTable = catDS.Tables["Products"];
// Create a relation between the Categories and Products tables.
DataRelation relation = catDS.Relations.Add("CatProdRel",
catTable.Columns["CategoryID"],
prodTable.Columns["CategoryID"]);
// Create DataViews for the Categories and Products tables.
DataView catView = new DataView(catTable, "", "CategoryName",
DataViewRowState.CurrentRows);
DataView prodView;
// Iterate through the Categories table.
foreach (DataRowView catDRV in catView)
{
Console.WriteLine(catDRV["CategoryName"]);
// Create a DataView of the child product records.
prodView = catDRV.CreateChildView(relation);
prodView.Sort = "ProductName";
foreach (DataRowView prodDRV in prodView)
Console.WriteLine("\t" + prodDRV["ProductName"]);
}