Control.BindingContext 屬性
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
取得或設定 BindingContext 控制。
public:
virtual property System::Windows::Forms::BindingContext ^ BindingContext { System::Windows::Forms::BindingContext ^ get(); void set(System::Windows::Forms::BindingContext ^ value); };
[System.ComponentModel.Browsable(false)]
public virtual System.Windows.Forms.BindingContext BindingContext { get; set; }
[System.ComponentModel.Browsable(false)]
public virtual System.Windows.Forms.BindingContext? BindingContext { get; set; }
[<System.ComponentModel.Browsable(false)>]
member this.BindingContext : System.Windows.Forms.BindingContext with get, set
Public Overridable Property BindingContext As BindingContext
屬性值
A BindingContext 代表控制。
實作
- 屬性
範例
以下程式碼範例建立四個 Binding 物件,將五個控制項(a DateTimePicker 和四個 TextBox 控制項)綁定到多個資料來源。 接著用來BindingContext取得每個資料來源的 。BindingManagerBase
void BindControls()
{
/* Create two Binding objects for the first two TextBox
controls. The data-bound property for both controls
is the Text property. The data source is a DataSet
(ds). The data member is a navigation path in the form:
"TableName.ColumnName". */
text1->DataBindings->Add( gcnew Binding( "Text",ds,"customers.custName" ) );
text2->DataBindings->Add( gcnew Binding( "Text",ds,"customers.custID" ) );
/* Bind the DateTimePicker control by adding a new Binding.
The data member of the DateTimePicker is a navigation path:
TableName.RelationName.ColumnName string. */
DateTimePicker1->DataBindings->Add( gcnew Binding( "Value",ds,"customers.CustToOrders.OrderDate" ) );
/* Add event delegates for the Parse and Format events to a
new Binding object, and add the object to the third
TextBox control's BindingsCollection. The delegates
must be added before adding the Binding to the
collection; otherwise, no formatting occurs until
the Current object of the BindingManagerBase for
the data source changes. */
Binding^ b = gcnew Binding( "Text",ds,"customers.custToOrders.OrderAmount" );
b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString );
text3->DataBindings->Add( b );
// Get the BindingManagerBase for the Customers table.
bmCustomers = this->BindingContext[ ds,"Customers" ];
/* Get the BindingManagerBase for the Orders table using the
RelationName. */
bmOrders = this->BindingContext[ds, "customers.CustToOrders"];
/* Bind the fourth TextBox control's Text property to the
third control's Text property. */
text4->DataBindings->Add( "Text", text3, "Text" );
}
protected void BindControls()
{
/* Create two Binding objects for the first two TextBox
controls. The data-bound property for both controls
is the Text property. The data source is a DataSet
(ds). The data member is a navigation path in the form:
"TableName.ColumnName". */
text1.DataBindings.Add(new Binding
("Text", ds, "customers.custName"));
text2.DataBindings.Add(new Binding
("Text", ds, "customers.custID"));
/* Bind the DateTimePicker control by adding a new Binding.
The data member of the DateTimePicker is a navigation path:
TableName.RelationName.ColumnName string. */
DateTimePicker1.DataBindings.Add(new
Binding("Value", ds, "customers.CustToOrders.OrderDate"));
/* Add event delegates for the Parse and Format events to a
new Binding object, and add the object to the third
TextBox control's BindingsCollection. The delegates
must be added before adding the Binding to the
collection; otherwise, no formatting occurs until
the Current object of the BindingManagerBase for
the data source changes. */
Binding b = new Binding
("Text", ds, "customers.custToOrders.OrderAmount");
b.Parse+=new ConvertEventHandler(CurrencyStringToDecimal);
b.Format+=new ConvertEventHandler(DecimalToCurrencyString);
text3.DataBindings.Add(b);
// Get the BindingManagerBase for the Customers table.
bmCustomers = this.BindingContext [ds, "Customers"];
/* Get the BindingManagerBase for the Orders table using the
RelationName. */
bmOrders = this.BindingContext[ds, "customers.CustToOrders"];
/* Bind the fourth TextBox control's Text property to the
third control's Text property. */
text4.DataBindings.Add("Text", text3, "Text");
}
Protected Sub BindControls()
' Create two Binding objects for the first two TextBox
' controls. The data-bound property for both controls
' is the Text property. The data source is a DataSet
' (ds). The data member is the string
' "TableName.ColumnName".
text1.DataBindings.Add(New Binding _
("Text", ds, "customers.custName"))
text2.DataBindings.Add(New Binding _
("Text", ds, "customers.custID"))
' Bind the DateTimePicker control by adding a new Binding.
' The data member of the DateTimePicker is a
' TableName.RelationName.ColumnName string.
DateTimePicker1.DataBindings.Add(New Binding _
("Value", ds, "customers.CustToOrders.OrderDate"))
' Add event delegates for the Parse and Format events to a
' new Binding object, and add the object to the third
' TextBox control's BindingsCollection. The delegates
' must be added before adding the Binding to the
' collection; otherwise, no formatting occurs until
' the Current object of the BindingManagerBase for
' the data source changes.
Dim b As Binding = New Binding _
("Text", ds, "customers.custToOrders.OrderAmount")
AddHandler b.Parse, New ConvertEventHandler(AddressOf CurrencyStringToDecimal)
AddHandler b.Format, New ConvertEventHandler(AddressOf DecimalToCurrencyString)
text3.DataBindings.Add(b)
' Get the BindingManagerBase for the Customers table.
bmCustomers = Me.BindingContext(ds, "Customers")
' Get the BindingManagerBase for the Orders table using the
' RelationName.
bmOrders = Me.BindingContext(ds, "customers.CustToOrders")
' Bind the fourth TextBox control's Text property to the
' third control's Text property.
text4.DataBindings.Add("Text", text3, "Text")
End Sub
備註
BindingContext a 的 Control 是用來回傳所有資料Control綁定控制項的 SingleBindingManagerBase。 它 BindingManagerBase 會讓綁定到同一資料來源的所有控制項保持同步。 例如,設定 Position 屬性 BindingManagerBase 即可指定底層清單中所有資料綁定控制項指向的項目。
欲了解更多關於建立新 BindingContext 資料並將其指派到該屬性的 BindingContext 資訊,請參閱 BindingContext。
給繼承者的注意事項
在導出類別中覆寫該 BindingContext 屬性時,請使用基底類別的 BindingContext 特性來擴充基底實作。 否則,你必須提供所有的實作。 你不必同時覆寫get該財產的setBindingContext附屬裝置;如果需要,你只能覆蓋其中一項。