DataSet.OnRemoveTable(DataTable) Metodo

Definizione

Spazio dei nomi:

System.Data

Assembly:

System.Data.Common.dll

Origine:

DataSet.cs

Viene generato quando si rimuove un oggetto DataTable da un oggetto DataSet.

protected public:
 virtual void OnRemoveTable(System::Data::DataTable ^ table);

protected internal virtual void OnRemoveTable (System.Data.DataTable table);

abstract member OnRemoveTable : System.Data.DataTable -> unit
override this.OnRemoveTable : System.Data.DataTable -> unit

Protected Friend Overridable Sub OnRemoveTable (table As DataTable)

Parametri

table

DataTable

Classe DataTable che viene rimossa.

Esempio

Nell'esempio seguente viene illustrata una classe derivata da DataSet con il OnRemoveTable metodo sottoposto a override.

public static void DemonstrateOnRemoveTable()
{
    DerivedDataSet dataSet = CreateDataSet();
    if(dataSet.Tables.Count > 0)
        dataSet.Tables.RemoveAt(0);
}

public class DerivedDataSet: DataSet
{
    protected override void OnRemoveTable(DataTable table)
    {
        Console.WriteLine(
            "The '{0}' DataTable has been removed from the DataSet",
            table.TableName);
    }
}

public static DerivedDataSet CreateDataSet()
{
    // Create a DataSet with one table containing two columns.
    DerivedDataSet derived = new DerivedDataSet();

    // Add table to DataSet.
    DataTable table = derived.Tables.Add("Items");

    // Add two columns.
    DataColumn column = table.Columns.Add("id", typeof(int));
    column.AutoIncrement = true;
    table.Columns.Add("item", typeof(int));

    // Set primary key.
    table.PrimaryKey = new DataColumn[] {table.Columns["id"]};

    return derived;
}

Public Shared Sub DemonstrateOnRemoveTable()
    Dim dataSet As DerivedDataSet = CreateDataSet()
    If dataSet.Tables.Count > 0 Then dataSet.Tables.RemoveAt(0)
End Sub

Public Class DerivedDataSet
    Inherits DataSet
    Protected Overrides Sub OnRemoveTable(table As DataTable)
        Console.WriteLine( _
            "The '{0}' DataTable has been removed from the DataSet", _
            table.TableName)
    End Sub
End Class

Public Shared Function CreateDataSet() As DerivedDataSet
    ' Create a DataSet with one table containing two columns.
    Dim derived As New DerivedDataSet()

    ' Add table to DataSet.
    Dim table As DataTable = derived.Tables.Add("Items")

    ' Add two columns.
    Dim column As DataColumn = table.Columns.Add("id", _
        Type.GetType("System.Int32"))
    column.AutoIncrement = True
    table.Columns.Add("item", Type.GetType("System.Int32"))

    ' Set primary key.
    table.PrimaryKey = New DataColumn() {table.Columns("id")}

    return derived
End Function

Commenti

Questo metodo può essere sottoposto a override da sottoclassi per limitare la rimozione delle tabelle.

Vedi anche

• Uso di DataSet in ADO.NET