DataSet.OnRemoveTable 方法
当从 DataSet 中移除 DataTable 时发生。
**命名空间:**System.Data
**程序集:**System.Data(在 system.data.dll 中)
语法
声明
Protected Friend Overridable Sub OnRemoveTable ( _
table As DataTable _
)
用法
Dim table As DataTable
Me.OnRemoveTable(table)
protected internal virtual void OnRemoveTable (
DataTable table
)
protected public:
virtual void OnRemoveTable (
DataTable^ table
)
protected void OnRemoveTable (
DataTable table
)
protected internal function OnRemoveTable (
table : DataTable
)
参数
- table
正在被移除的 DataTable。
备注
此方法可被子类重写以限制表被移除。
示例
下面的示例显示当 OnRemoveTable 方法被重写时从 DataSet 派生的类。
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;
}
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表,请参见系统要求。
版本信息
.NET Framework
受以下版本支持:2.0、1.1、1.0
.NET Compact Framework
受以下版本支持:2.0、1.0
请参见
参考
DataSet 类
DataSet 成员
System.Data 命名空间