Control.OnEnter Method (EventArgs)

 

Raises the Enter event.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Protected Overridable Sub OnEnter (
	e As EventArgs
)

Parameters

e
Type: System.EventArgs

An EventArgs that contains the event data.

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 in a derived class, be sure to call the base class's OnEnter method so that registered delegates receive the event.

The following code example uses the Enter event to change the foreground and background colors of a TextBox under particular conditions.

    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 'textBox1_Enter


    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 'textBox1_Leave
End Class 'Form1 

.NET Framework
Available since 1.1
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