BindingManagerBase 類別

定義

public ref class BindingManagerBase abstract

public abstract class BindingManagerBase

type BindingManagerBase = class

Public MustInherit Class BindingManagerBase

繼承

Object

BindingManagerBase

衍生

System.Windows.Forms.CurrencyManager

System.Windows.Forms.PropertyManager

範例

下列程式碼範例會使用 BindingContext 傳回 BindingManagerBase 特定資料來源的 。 (此範例假設您已在 module.) 的宣告區段中宣告 myBindingManagerBase 此範例，然後將事件委派新增至 CurrentChanged 和 PositionChanged 事件。 最後，此範例包含四個方法 (、、 和 MoveLast) 遞增或遞減 Position 屬性，並將 設定 Position 為清單中的第一個或最後一個資料 MoveFirst 列。 MovePreviousMoveNext 清單中的最後一個資料列是使用 Count 屬性來決定。

void GetBindingManagerBase()
{
   
   /* CustomersToOrders is the RelationName of a DataRelation. 
      Therefore, the list maintained by the BindingManagerBase is the
      list of orders that belong to a specific customer in the 
      DataTable named Customers, found in DataSet1. */
   myBindingManagerBase = this->BindingContext[DataSet1, "Customers.CustomersToOrders"];
   
   // Adds delegates to the CurrentChanged and PositionChanged events.
   myBindingManagerBase->PositionChanged += gcnew EventHandler( this, &Form1::BindingManagerBase_PositionChanged );
   myBindingManagerBase->CurrentChanged += gcnew EventHandler( this, &Form1::BindingManagerBase_CurrentChanged );
}

void BindingManagerBase_PositionChanged( Object^ sender, EventArgs^ /*e*/ )
{
   
   // Prints the new Position of the BindingManagerBase.
   Console::Write( "Position Changed: " );
   Console::WriteLine( (dynamic_cast<BindingManagerBase^>(sender))->Position );
}

void BindingManagerBase_CurrentChanged( Object^ sender, EventArgs^ /*e*/ )
{
   
   // Prints the new value of the current object.
   Console::Write( "Current Changed: " );
   Console::WriteLine( (dynamic_cast<BindingManagerBase^>(sender))->Current );
}

void MoveNext()
{
   
   // Increments the Position property value by one.
   myBindingManagerBase->Position = myBindingManagerBase->Position + 1;
}

void MovePrevious()
{
   
   // Decrements the Position property value by one.
   myBindingManagerBase->Position = myBindingManagerBase->Position - 1;
}

void MoveFirst()
{
   
   // Goes to the first row in the list.
   myBindingManagerBase->Position = 0;
}

void MoveLast()
{
   
   // Goes to the last row in the list.
   myBindingManagerBase->Position = myBindingManagerBase->Count - 1;
}

private void GetBindingManagerBase()
{
   /* CustomersToOrders is the RelationName of a DataRelation. 
   Therefore, the list maintained by the BindingManagerBase is the
   list of orders that belong to a specific customer in the 
   DataTable named Customers, found in DataSet1. */
   myBindingManagerBase = 
   this.BindingContext[DataSet1, "Customers.CustomersToOrders"];

   // Adds delegates to the CurrentChanged and PositionChanged events.
   myBindingManagerBase.PositionChanged += 
   new EventHandler(BindingManagerBase_PositionChanged);
   myBindingManagerBase.CurrentChanged +=
   new EventHandler(BindingManagerBase_CurrentChanged);
}

private void BindingManagerBase_PositionChanged
(object sender, EventArgs e)
{
   // Prints the new Position of the BindingManagerBase.
   Console.Write("Position Changed: ");
   Console.WriteLine(((BindingManagerBase)sender).Position);
}

private void BindingManagerBase_CurrentChanged
(object sender, EventArgs e)
{
   // Prints the new value of the current object.
   Console.Write("Current Changed: ");
   Console.WriteLine(((BindingManagerBase)sender).Current);
}

private void MoveNext()
{
   // Increments the Position property value by one.
   myBindingManagerBase.Position += 1;
}

private void MovePrevious()
{
   // Decrements the Position property value by one.
   myBindingManagerBase.Position -= 1;
}

private void MoveFirst()
{
   // Goes to the first row in the list.
   myBindingManagerBase.Position = 0;
}

private void MoveLast()
{
   // Goes to the last row in the list.
   myBindingManagerBase.Position = 
   myBindingManagerBase.Count - 1;
}

Private Sub GetBindingManagerBase
   ' CustomersToOrders is the RelationName of a DataRelation.
   ' Therefore, the list maintained by the BindingManagerBase is the
   ' list of orders that belong to a specific customer in the
   ' DataTable named Customers, found in DataSet.
   myBindingManagerBase = Me.BindingContext(DataSet1, _
   "Customers.CustomersToOrders")

   ' Adds delegates to the CurrentChanged and PositionChanged events.
   AddHandler myBindingManagerBase.PositionChanged, _
   AddressOf BindingManagerBase_PositionChanged
   AddHandler myBindingManagerBase.CurrentChanged, _
   AddressOf BindingManagerBase_CurrentChanged
End Sub

Private Sub BindingManagerBase_PositionChanged _
(sender As Object, e As EventArgs)

   ' Prints the new Position of the BindingManagerBase.
   Console.Write("Position Changed: ")
   Console.WriteLine(CType(sender, BindingManagerBase).Position)
End Sub

Private Sub BindingManagerBase_CurrentChanged _
(sender As Object, e As EventArgs)

   ' Prints the new value of the current object.
   Console.Write("Current Changed: ")
   Console.WriteLine(CType(sender, BindingManagerBase).Current)
End Sub

Private Sub MoveNext
   ' Increments the Position property value by one.
   myBindingManagerBase.Position += 1
End Sub

Private Sub MovePrevious
   ' Decrements the Position property value by one.
   myBindingManagerBase.Position -= 1
End Sub

Private Sub MoveFirst
   ' Goes to the first row in the list.
   myBindingManagerBase.Position = 0
End Sub

Private Sub MoveLast
   ' Goes to the last row in the list.
   myBindingManagerBase.Position = _
   myBindingManagerBase.Count - 1
End Sub

備註

可讓您 BindingManagerBase 在系結至相同資料來源的 Windows Form 上同步處理資料繫結控制項。 (如需將控制項系結至資料來源的詳細資訊，請參閱 Binding class.) 例如，假設表單包含兩 TextBox 個系結至相同資料來源但系結至不同資料行的控制項。 資料來源可能是 DataTable 包含客戶名稱的 ，而資料行可能包含名字和姓氏。 這兩個控制項必須同步處理，才能為相同的客戶一起顯示正確的名字和姓氏。 繼承自 類別的 BindingManagerBase ， CurrencyManager 藉由維護資料來源中目前專案的指標來完成這項同步處理。 控制項 TextBox 會系結至目前的專案，以便顯示相同資料列的資訊。 當目前的專案變更時，會 CurrencyManager 通知所有繫結控制項，以便重新整理其資料。 此外，您可以設定 Position 屬性，以指定控制項指向的資料 DataTable 列。 若要判斷資料來源中有多少個數據列，請使用 Count 屬性。

CurrencyManager是必要的，因為資料來源不一定會維護目前的專案指標。 例如，陣列和 ArrayList 物件可以是資料來源，但它們沒有傳回目前專案的屬性。 若要取得目前的專案，請使用 Current 屬性。

PropertyManager也會繼承自 BindingManagerBase ，並且用來維護物件的目前屬性，而不是資料來源中目前物件的 屬性。 基於這個理由，嘗試設定 Position 的 或 Count 屬性 PropertyManager 沒有任何作用。

若要建立 BindingManagerBase ，請使用 BindingContext 類別，其會根據所管理的資料來源傳回 CurrencyManager 或 PropertyManager 。

我們鼓勵解決方案程式設計人員將控制項直接系結至 BindingSource 元件，這同時作為資料來源和資料連線器，以作為實際目標資料來源。 BindingSource 大幅簡化簡單和複雜的資料系結，包括管理控制項與其目標之間的貨幣。

給實施者的注意事項

當您繼承自 BindingManagerBase 時，必須覆寫下列抽象成員： AddNew() 、、 CountGetItemProperties()CancelCurrentEdit()OnCurrentChanged(EventArgs)EndCurrentEdit()Current 、、 RemoveAt(Int32)ResumeBinding()PositionSuspendBinding() 和 。 UpdateIsBinding()

建構函式

欄位

屬性

方法

事件

適用於

另請參閱

• BindingSource
• BindingContext
• CurrencyManager
• PropertyManager