Control.RightToLeftChanged 事件

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

在 RightToLeft 属性值更改时发生。

public:
 event EventHandler ^ RightToLeftChanged;

public event EventHandler? RightToLeftChanged;

member this.RightToLeftChanged : EventHandler 

Public Custom Event RightToLeftChanged As EventHandler 

事件类型

EventHandler

示例

下面的代码示例是属性值更改时 Text 执行的事件处理程序。 类Control具有多个名称模式 PropertyName 的方法，这些方法在相应的 PropertyNameChanged 值更改时引发 (PropertyName 表示) 相应属性的名称。

下面的代码示例更改ForeColorTextBox显示货币数据的 。 该示例将文本转换为十进制数，如果数字为负数，则将 更改为 ForeColorColor.Red ;如果该数字为正数，则更改为 Color.Black 。 此示例要求具有 Form 包含 的 TextBox。

private:
   void currencyTextBox_TextChanged( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      try
      {
         // Convert the text to a Double and determine if it is a negative number.
         if ( Double::Parse( currencyTextBox->Text ) < 0 )
         {
            // If the number is negative, display it in Red.
            currencyTextBox->ForeColor = Color::Red;
         }
         else
         {
            // If the number is not negative, display it in Black.
            currencyTextBox->ForeColor = Color::Black;
         }
      }
      catch ( Exception^ ) 
      {
         // If there is an error, display the text using the system colors.
         currencyTextBox->ForeColor = SystemColors::ControlText;
      }
   }

private void currencyTextBox_TextChanged(object sender, EventArgs e)
{
   try
   {
      // Convert the text to a Double and determine if it is a negative number.
      if(double.Parse(currencyTextBox.Text) < 0)
      {
         // If the number is negative, display it in Red.
         currencyTextBox.ForeColor = Color.Red;
      }
      else
      {
         // If the number is not negative, display it in Black.
         currencyTextBox.ForeColor = Color.Black;
      }
   }
   catch
   {
      // If there is an error, display the text using the system colors.
      currencyTextBox.ForeColor = SystemColors.ControlText;
   }
}

Private Sub currencyTextBox_TextChanged(sender As Object, _ 
  e As EventArgs) Handles currencyTextBox.TextChanged
   Try
      ' Convert the text to a Double and determine if it is a negative number.
      If Double.Parse(currencyTextBox.Text) < 0 Then
         ' If the number is negative, display it in Red.
         currencyTextBox.ForeColor = Color.Red
      Else
         ' If the number is not negative, display it in Black.
         currencyTextBox.ForeColor = Color.Black
      End If
   Catch
      ' If there is an error, display the text using the system colors.
      currencyTextBox.ForeColor = SystemColors.ControlText
   End Try
End Sub

注解

如果通过编程修改或用户交互更改属性， RightToLeft 则会引发此事件。

有关处理事件的详细信息，请参阅 处理和引发事件。

另请参阅

• OnRightToLeftChanged(EventArgs)
• RightToLeft