Control.OnEnter(EventArgs) Method
Definition
Important
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Raises the Enter event.
protected:
virtual void OnEnter(EventArgs ^ e);
protected public:
virtual void OnEnter(EventArgs ^ e);
protected virtual void OnEnter (EventArgs e);
protected internal virtual void OnEnter (EventArgs e);
abstract member OnEnter : EventArgs -> unit
override this.OnEnter : EventArgs -> unit
Protected Overridable Sub OnEnter (e As EventArgs)
Protected Friend Overridable Sub OnEnter (e As EventArgs)
Parameters
Examples
The following code example uses the Enter event to change the foreground and background colors of a TextBox under particular conditions.
private:
void textBox1_Enter( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
// If the TextBox contains text, change its foreground and background colors.
if ( textBox1->Text != String::Empty )
{
textBox1->ForeColor = Color::Red;
textBox1->BackColor = Color::Black;
// Move the selection pointer to the end of the text of the control.
textBox1->Select(textBox1->Text->Length,0);
}
}
void textBox1_Leave( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
// Reset the colors and selection of the TextBox after focus is lost.
textBox1->ForeColor = Color::Black;
textBox1->BackColor = Color::White;
textBox1->Select(0,0);
}
private void textBox1_Enter(object sender, System.EventArgs e)
{
// If the TextBox contains text, change its foreground and background colors.
if (!string.IsNullOrEmpty(textBox1.Text))
{
textBox1.ForeColor = Color.Red;
textBox1.BackColor = Color.Black;
// Move the selection pointer to the end of the text of the control.
textBox1.Select(textBox1.Text.Length, 0);
}
}
private void textBox1_Leave(object sender, System.EventArgs e)
{
// Reset the colors and selection of the TextBox after focus is lost.
textBox1.ForeColor = Color.Black;
textBox1.BackColor = Color.White;
textBox1.Select(0,0);
}
Private Sub textBox1_Enter(sender As Object, e As System.EventArgs) Handles textBox1.Enter
' If the TextBox contains text, change its foreground and background colors.
If textBox1.Text <> [String].Empty Then
textBox1.ForeColor = Color.Red
textBox1.BackColor = Color.Black
' Move the selection pointer to the end of the text of the control.
textBox1.Select(textBox1.Text.Length, 0)
End If
End Sub
Private Sub textBox1_Leave(sender As Object, e As System.EventArgs) Handles textBox1.Leave
' Reset the colors and selection of the TextBox after focus is lost.
textBox1.ForeColor = Color.Black
textBox1.BackColor = Color.White
textBox1.Select(0, 0)
End Sub
End Class
Remarks
Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.
The OnEnter 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 OnEnter(EventArgs) in a derived class, be sure to call the base class's OnEnter(EventArgs) method so that registered delegates receive the event.
Applies to
See also
Athugasemdir
https://aka.ms/ContentUserFeedback.
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