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ChildView et relations

Si une relation existe entre les tables d'un DataSet, vous pouvez créer un DataView contenant les lignes de la table enfant associée en utilisant la méthode CreateChildView de DataRowView pour les lignes de la table parente. Par exemple, le code suivant affiche Categories et leurs éléments associés Products dans l'ordre alphabétique trié par CategoryName et par le nom de produit 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"]);
}

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