Binding.Parse 事件

项目
08/17/2007

在数据绑定控件的值更改时发生。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Event Parse As ConvertEventHandler
用法
Dim instance As Binding
Dim handler As ConvertEventHandler

AddHandler instance.Parse, handler

public event ConvertEventHandler Parse

public:
event ConvertEventHandler^ Parse {
    void add (ConvertEventHandler^ value);
    void remove (ConvertEventHandler^ value);
}

/** @event */
public void add_Parse (ConvertEventHandler value)

/** @event */
public void remove_Parse (ConvertEventHandler value)

JScript 支持使用事件，但不支持进行新的声明。

备注

Format 事件和 Parse 事件允许您创建自定义格式来显示数据。例如，如果表中的数据为 Decimal 类型，则可以通过将 ConvertEventArgs 的 Value 属性设置为 Format 事件中的格式化值，从而用本地货币格式显示数据。因此，必须取消 Parse 事件中显示的值的格式。

Parse 事件在下列条件下发生：

在 Control 的 Validated 事件发生之后。
当调用 BindingManagerBase 的 EndCurrentEdit 方法时。
当 BindingManagerBase 的 Current 发生更改时（也就是当 Position 发生更改时）。

有关处理事件的更多信息，请参见使用事件。

示例

下面的代码示例创建一个 Binding，向 Parse 事件和 Format 事件添加 ConvertEventHandler 委托，并通过 DataBindings 属性向 TextBox 控件的 BindingsCollection 添加 Binding。添加到 Format 事件的 DecimalToCurrencyString 事件委托使用 ToString 方法将绑定值（Decimal 类型）格式化为货币类型。添加到 Parse 事件的 CurrencyStringToDecimal 事件委托将控件所显示的值转换回 Decimal 类型。

Private Sub DecimalToCurrencyString(sender As Object, cevent As ConvertEventArgs)
    ' The method converts only to string type. Test this using the DesiredType.
    If Not cevent.DesiredType Is GetType(String) Then
        Exit Sub
    End If
    
    ' Use the ToString method to format the value as currency ("c").
    cevent.Value = CType(cevent.Value, decimal).ToString("c")
End Sub

Private Sub CurrencyStringToDecimal(sender As Object, cevent As ConvertEventArgs)
    ' The method converts back to decimal type only.
    If Not cevent.DesiredType Is GetType(Decimal) Then
        Exit Sub
    End If

    ' Convert the string back to decimal using the shared Parse method.
   cevent.Value = Decimal.Parse(cevent.Value.ToString, _
  NumberStyles.Currency, nothing)

End Sub

Private Sub BindControl
    ' Create the binding first. The OrderAmount is typed as Decimal.
    Dim b As Binding = New Binding _
        ("Text", ds, "Customers.custToOrders.OrderAmount")
    ' Add the delegates to the event.
    AddHandler b.Format, AddressOf DecimalToCurrencyString
    AddHandler b.Parse, AddressOf CurrencyStringToDecimal
    text1.DataBindings.Add(b)
End Sub

private void DecimalToCurrencyString(object sender, ConvertEventArgs cevent)
{
   // The method converts only to string type. Test this using the DesiredType.
   if(cevent.DesiredType != typeof(string)) return;

   // Use the ToString method to format the value as currency ("c").
   cevent.Value = ((decimal) cevent.Value).ToString("c");
}

private void CurrencyStringToDecimal(object sender, ConvertEventArgs cevent)
{
   // The method converts back to decimal type only.
   if(cevent.DesiredType != typeof(decimal)) return;

   // Converts the string back to decimal using the static Parse method.
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

private void BindControl()
{
   // Creates the binding first. The OrderAmount is typed as Decimal.
   Binding b = new Binding
      ("Text", ds, "customers.custToOrders.OrderAmount");
   // Add the delegates to the event.
   b.Format += new ConvertEventHandler(DecimalToCurrencyString);
   b.Parse += new ConvertEventHandler(CurrencyStringToDecimal);
   text1.DataBindings.Add(b);
}

private:
   void DecimalToCurrencyString( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      // The method converts only to string type. Test this using the DesiredType.
      if ( cevent->DesiredType != String::typeid )
      {
         return;
      }
      
      // Use the ToString method to format the value as currency ("c").
      cevent->Value = ( (Decimal)(cevent->Value) ).ToString( "c" );
   }

   void CurrencyStringToDecimal( Object^ /*sender*/, ConvertEventArgs^ cevent )
   {
      // The method converts back to decimal type only.
      if ( cevent->DesiredType != Decimal::typeid )
      {
         return;
      }
      
      // Converts the string back to decimal using the static Parse method.
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }

   void BindControl()
   {
      // Creates the binding first. The OrderAmount is typed as Decimal.
      Binding^ b = gcnew Binding(
         "Text", ds, "customers.custToOrders.OrderAmount" );
      // Add the delegates to the event.
      b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString );
      b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
      text1->DataBindings->Add( b );
   }

private void DecimalToCurrencyString(Object sender, ConvertEventArgs cevent)
{
    // The method converts only to string type. Test this using 
    // the DesiredType.
    if (!cevent.get_DesiredType().Equals(String.class.ToType())) {
        return;
    }
    // Use the ToString method to format the value as currency ("c").
    cevent.set_Value(((System.Decimal)(cevent.get_Value())).ToString("c"));
} //DecimalToCurrencyString

private void CurrencyStringToDecimal(Object sender, ConvertEventArgs cevent)
{
    // The method converts back to decimal type only.
    if (!cevent.get_DesiredType().Equals(System.Decimal.class.ToType())) {
        return;
    }
    // Converts the string back to decimal using the static Parse method.
    cevent.set_Value(Decimal.Parse(cevent.get_Value().ToString(), 
        NumberStyles.Currency, null));
} //CurrencyStringToDecimal

private void BindControl()
{
    // Creates the binding first. The OrderAmount is typed as Decimal.
    Binding b = new Binding("Text", ds,
        "customers.custToOrders.OrderAmount");
    // Add the delegates to the event.
    b.add_Format(new ConvertEventHandler(DecimalToCurrencyString));
    b.add_Parse(new ConvertEventHandler(CurrencyStringToDecimal));
    text1.get_DataBindings().Add(b);
} //BindControl

private function DecimalToCurrencyString(sender, cevent : ConvertEventArgs)
{
   // The method converts only to string type. Test this using the DesiredType.
   if(cevent.DesiredType != String.GetType()) return;

   cevent.Value = (Decimal(cevent.Value)).ToString("c"); 
}

private function CurrencyStringToDecimal(sender, cevent : ConvertEventArgs)
{
   // The method converts back to decimal type only. 
   if(cevent.DesiredType != Decimal.GetType()) return;

   // Converts the string back to decimal using the static Parse method.
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

private function BindControl()
{
   // Creates the binding first. The OrderAmount is a Decimal type.
   var b : Binding = new Binding
      ("Text", ds, "Suppliers.CompanyName");
   // Add the delegates to the event.
   b.add_Format(DecimalToCurrencyString);
   b.add_Parse(CurrencyStringToDecimal);
   text1.DataBindings.Add(b);
}

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

Binding 类
 Binding 成员
 System.Windows.Forms 命名空间
 Binding.Format 事件
 OnParse
PositionChanged
CurrentChanged

Binding.Parse 事件

语法

备注

示例

平台

版本信息

.NET Framework

.NET Compact Framework

请参见

参考

其他资源