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Control.OnBindingContextChanged Method

Raises the BindingContextChanged event.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

protected virtual void OnBindingContextChanged (
	EventArgs e
)
protected void OnBindingContextChanged (
	EventArgs e
)
protected function OnBindingContextChanged (
	e : EventArgs
)

Parameters

e

An EventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.

The OnBindingContextChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors When overriding OnBindingContextChanged in a derived class, be sure to call the base class's OnBindingContextChanged method so that registered delegates receive the event.

The following code example is an event-raising method that is executed when the Text property value changes. The Control class has several methods with the name pattern On <PropertyName> Changed that raise the corresponding event when the property value changes. You can create an event-raising method similar to the following code example to raise the appropriate event when the corresponding property value changes.

The following code example changes the ForeColor of a TextBox derived class 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 class that derives from the TextBox class.

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

protected void OnTextChanged(System.EventArgs e)
{
    try {
        // Convert the text to a Double and determine
        // if it is a negative number.
        if (System.Double.Parse(this.get_Text()) < 0) {
            // If the number is negative, display it in Red.
            this.set_ForeColor(Color.get_Red());
        }
        else {
            // If the number is not negative, display it in Black.
            this.set_ForeColor(Color.get_Black());
        }
    }
    catch (System.Exception exp) {
        // If there is an error, display the 
        // text using the system colors.
        this.set_ForeColor(SystemColors.get_ControlText());
    }
    super.OnTextChanged(e);
} //OnTextChanged

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

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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