BindingsCollection 类

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

代表某控件的 Binding 对象的集合。

public ref class BindingsCollection : System::Windows::Forms::BaseCollection

public class BindingsCollection : System.Windows.Forms.BaseCollection

type BindingsCollection = class
    inherit BaseCollection

Public Class BindingsCollection
Inherits BaseCollection

继承

Object

MarshalByRefObject

BaseCollection

BindingsCollection

派生

System.Windows.Forms.ControlBindingsCollection

示例

以下示例将 Text 控件的 TextBox 属性绑定到数据库中的字段。

private:
   void BindTextBoxControl()
   {
      DataSet^ myDataSet = gcnew DataSet;
      /* Insert code to populate the DataSet with tables, 
      columns, and data. */

      // Creates a new Binding object. 
      Binding^ myBinding = gcnew Binding(
         "Text",myDataSet,"customers.custToOrders.OrderAmount" );
      
      // Adds event delegates for the Parse and Format events.
      myBinding->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyToDecimal );
      myBinding->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrency );
      
      // Adds the new Binding to the BindingsCollection.
      text1->DataBindings->Add( myBinding );
   }

   void DecimalToCurrency( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      /* This method is the Format event handler. Whenever the 
      control displays a new value, the value is converted from 
      its native Decimal type to a string. The ToString method 
      then formats the value as a Currency, by using the 
      formatting character "c". */
      cevent->Value = safe_cast<Decimal ^>(cevent->Value)->ToString(  "c" );
   }

   void CurrencyToDecimal( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      /* This method is the Parse event handler. The Parse event 
      occurs whenever the displayed value changes. The static 
      Parse method of the Decimal structure converts the 
      string back to its native Decimal type. */
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }

private void BindTextBoxControl()
{
   DataSet myDataSet = new DataSet();
   /* Insert code to populate the DataSet with tables, 
   columns, and data. */

   // Creates a new Binding object. 
   Binding myBinding = new Binding
   ("Text", myDataSet, "customers.custToOrders.OrderAmount");

   // Adds event delegates for the Parse and Format events.
   myBinding.Parse += new ConvertEventHandler(CurrencyToDecimal);
   myBinding.Format += new ConvertEventHandler(DecimalToCurrency);

   // Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding);
}

private void DecimalToCurrency(object sender, 
   ConvertEventArgs cevent)
{
   /* This method is the Format event handler. Whenever the 
   control displays a new value, the value is converted from 
   its native Decimal type to a string. The ToString method 
   then formats the value as a Currency, by using the 
   formatting character "c". */
   cevent.Value = ((decimal) cevent.Value).ToString("c");
}

private void CurrencyToDecimal(object sender, 
   ConvertEventArgs cevent)
{   
   /* This method is the Parse event handler. The Parse event 
   occurs whenever the displayed value changes. The static 
   Parse method of the Decimal structure converts the 
   string back to its native Decimal type. */
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

Private Sub BindTextBoxControl()
   Dim myDataSet As New DataSet()
   ' Insert code to populate the DataSet with tables, columns, and data.

   ' Creates a new Binding object. 
   Dim myBinding As New Binding("Text", myDataSet, _
   "customers.custToOrders.OrderAmount")
   
   ' Adds event delegates for the Parse and Format events.
   AddHandler myBinding.Parse, AddressOf CurrencyToDecimal
   AddHandler myBinding.Format, AddressOf DecimalToCurrency
     
   ' Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding)
End Sub 
    
Private Sub DecimalToCurrency(sender As Object, _
   cevent As ConvertEventArgs)
   ' This method is the Format event handler. Whenever the
   ' control displays a new value, the value is converted from
   ' its native Decimal type to a string. The ToString method
   ' then formats the value as a Currency, by using the
   ' formatting character "c". 
   cevent.Value = CDec(cevent.Value).ToString("c")
End Sub 
    
Private Sub CurrencyToDecimal(sender As Object, _
cevent As ConvertEventArgs)
   ' This method is the Parse event handler. The Parse event
   ' occurs whenever the displayed value changes. The static
   ' Parse method of the Decimal structure converts the 
   ' string back to its native Decimal type. 
   cevent.Value = Decimal.Parse(cevent.Value.ToString(), _
   NumberStyles.Currency, nothing)
   End Sub

注解

简单数据绑定是通过将 对象添加到 Binding 来完成的 BindingsCollection。 从 Control 类继承的任何对象都可以通过 DataBindings 属性访问 BindingsCollection 。 有关支持数据绑定的 Windows 控件的列表，请参阅 Binding 类。

属性

Count	获取集合中绑定的总数。
IsReadOnly	获取一个值，该值指示集合是否为只读。 (继承自 BaseCollection)
IsSynchronized	获取一个值，该值指示对 ICollection 的访问是否同步。 (继承自 BaseCollection)
Item[Int32]	获取位于指定索引处的 Binding。
List	获取集合中作为对象的绑定。
SyncRoot	获取可用于同步对 BaseCollection 的访问的对象。 (继承自 BaseCollection)

方法

Add(Binding)	将指定的绑定添加到集合。
AddCore(Binding)	将 Binding 添加到集合。
Clear()	清除绑定对象的集合。
ClearCore()	清除所有成员的集合。
CopyTo(Array, Int32)	将当前一维 Array 的所有元素复制到指定的一维 Array 中（从指定的目标 Array 索引开始）。 (继承自 BaseCollection)
CreateObjRef(Type)	创建一个对象，该对象包含生成用于与远程对象进行通信的代理所需的全部相关信息。 (继承自 MarshalByRefObject)
Equals(Object)	确定指定对象是否等于当前对象。 (继承自 Object)
GetEnumerator()	获取能够循环访问集合成员的对象。 (继承自 BaseCollection)
GetHashCode()	作为默认哈希函数。 (继承自 Object)
GetLifetimeService()	检索控制此实例的生存期策略的当前生存期服务对象。 (继承自 MarshalByRefObject)
GetType()	获取当前实例的 Type。 (继承自 Object)
InitializeLifetimeService()	获取生存期服务对象来控制此实例的生存期策略。 (继承自 MarshalByRefObject)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
MemberwiseClone(Boolean)	创建当前 MarshalByRefObject 对象的浅表副本。 (继承自 MarshalByRefObject)
OnCollectionChanged(CollectionChangeEventArgs)	引发 CollectionChanged 事件。
OnCollectionChanging(CollectionChangeEventArgs)	引发 CollectionChanging 事件。
Remove(Binding)	从集合中删除指定的绑定。
RemoveAt(Int32)	从集合中删除指定索引处的绑定。
RemoveCore(Binding)	从集合中移除指定的 Binding。
ShouldSerializeMyAll()	获取指示是否应序列化集合的值。
ToString()	返回表示当前对象的字符串。 (继承自 Object)

事件

CollectionChanged	在集合更改后发生。
CollectionChanging	在集合即将更改时发生。

扩展方法

另请参阅

• CurrencyManager