Control.TextChanged Control.TextChanged Control.TextChanged Control.TextChanged Event

定義

發生在 Text 屬性值變更時。Occurs when the Text property value changes.

public:
 event EventHandler ^ TextChanged;
public event EventHandler TextChanged;
member this.TextChanged : EventHandler 
Public Custom Event TextChanged As EventHandler 

範例

下列程式碼範例會變更ForeColorTextBox顯示貨幣資料。The following code example changes the ForeColor of a TextBox displaying currency data. 此範例會將文字轉換成十進位數字和變更ForeColorColor.Red如果數字為負數,Color.Black如果數字為正數。The example converts the text to a decimal number and changes the ForeColor to Color.Red if the number is negative and to Color.Black if the number is positive. 此範例中,您需要Form,其中包含TextBoxThis example requires that you have a Form that contains a 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 

備註

如果會引發這個事件Text屬性會變更以程式設計方式修改或使用者互動。This event is raised if the Text property is changed by either a programmatic modification or user interaction.

如需有關如何處理事件的詳細資訊,請參閱 < 處理和引發事件For more information about handling events, see Handling and Raising Events.

適用於

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