DataSet.OnRemoveTable(DataTable) 方法

定义

命名空间:

System.Data

程序集:

System.Data.Common.dll

Source:

DataSet.cs

当从 DataTable 中移除 DataSet 时发生。

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)

参数

table

DataTable

正在移除的 DataTable。

示例

以下示例演示一个从 派生的 DataSet 类， OnRemoveTable 并重写 了 方法。

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

注解

此方法可由子类重写，以限制表被删除。

另请参阅

• 在 ADO.NET 中使用数据集