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Control.BackColorChanged Event

  • Reference

Definition

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll

Occurs when the value of the BackColor property changes.

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

Event Type

EventHandler

Examples

The following code example is an event handler that is executed when the Text property value changes. The Control class has several methods with the name pattern PropertyNameChanged that are raised when the corresponding PropertyName value changes (PropertyName represents the name of the corresponding property).

The following code example changes the ForeColor of a TextBox displaying currency data. 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. 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

Remarks

This event is raised if the BackColor property is changed by either a programmatic modification or user interaction.

For more information about handling events, see Handling and Raising Events.

Applies to

See also