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

定义

命名空间:
System.Windows.Forms System.Windows.Forms System.Windows.Forms System.Windows.Forms
Assembly:
System.Windows.Forms.dll

在 Text 属性值更改时发生。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

示例

下面的代码示例中更改ForeColor的TextBox显示货币数据。The following code example changes the ForeColor of a TextBox displaying currency data. 此示例将文本转换为十进制数字，并更改ForeColor到Color.Red如果数字为负数和Color.Black如果数字为正数。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. 此示例要求具有Form，其中包含TextBox。This 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

注解

如果引发此事件Text属性更改通过以编程方式修改或用户交互。This event is raised if the Text property is changed by either a programmatic modification or user interaction.

有关处理事件的详细信息，请参阅处理和引发事件。For more information about handling events, see Handling and Raising Events.

适用于

另请参阅