DataSet.OnRemoveTable メソッドとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

DataSet.OnRemoveTable メソッド

DataSet から DataTable が削除されたときに発生します。

名前空間: System.Data
アセンブリ: System.Data (system.data.dll 内)
構文

Visual Basic (宣言)

Protected Friend Overridable
 Sub OnRemoveTable ( _
    table As DataTable _
)

Visual Basic (使用法)

Dim table As DataTable

Me.OnRemoveTable(table)

protected internal virtual void OnRemoveTable
 (
    DataTable table
)

C++

protected public:
virtual void OnRemoveTable (
    DataTable^ table
)

protected void OnRemoveTable (
    DataTable table
)

JScript

protected internal function
 OnRemoveTable (
    table : DataTable
)

パラメータ

table: 削除する DataTable。

解説

このメソッドをサブクラスでオーバーライドして、テーブルの削除を制限できます。

使用例

OnRemoveTable メソッドをオーバーライドした DataSet から派生したクラスを次の例に示します。

Visual Basic

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 DerivedDataSet = 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

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;
}