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Control.OnMouseHover Method

Raises the MouseHover event.

[Visual Basic]
Protected Overridable Sub OnMouseHover( _
   ByVal e As EventArgs _
)
[C#]
protected virtual void OnMouseHover(
 EventArgs e
);
[C++]
protected: virtual void OnMouseHover(
 EventArgs* e
);
[JScript]
protected function OnMouseHover(
   e : EventArgs
);

Parameters

e
An EventArgs that contains the event data.

Remarks

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

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

Example

[Visual Basic, C#] The following code example demonstrates how to override the OnMouseHover and the OnMouseMove methods in a derived class. To run the example, paste the following code in a new form and paste this class, forming the same file, after the form. Add a button of type FunButton to the form.

[Visual Basic] 
Public Class FunButton
    Inherits Button

    Protected Overrides Sub OnMouseHover(ByVal e As System.EventArgs)

        ' Get the font size in Points, add one to the
        ' size, and reset the button's font to the larger
        ' size.
        Dim fontSize As Single = Font.SizeInPoints
        fontSize += 1
        Dim buttonSize As System.Drawing.Size = Size
        Me.Font = New System.Drawing.Font _
            (Font.FontFamily, fontSize, Font.Style)

        ' Increase the size width and height of the button 
        ' by 5 points each.
        Size = New System.Drawing.Size _
            (Size.Width + 5, Size.Height + 5)

        ' Call myBase.OnMouseHover to activate the delegate.
        MyBase.OnMouseHover(e)
    End Sub

    Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)

        ' Make the curser the Hand curser when the mouse moves 
        ' over the button.
        Cursor = Cursors.Hand

        ' Call MyBase.OnMouseHover to activate the delegate.
        MyBase.OnMouseHover(e)
    End Sub

[C#] 
public class FunButton:
    Button

{
    protected override void OnMouseHover(System.EventArgs e)
    {

        // Get the font size in Points, add one to the
        // size, and reset the button's font to the larger
        // size.
        float fontSize = Font.SizeInPoints;
        fontSize += 1;
        System.Drawing.Size buttonSize = Size;
        this.Font = new System.Drawing.Font(
            Font.FontFamily, fontSize, Font.Style);

        // Increase the size width and height of the button 
        // by 5 points each.
        Size = new System.Drawing.Size(Size.Width+5, Size.Height+5);

        // Call myBase.OnMouseHover to activate the delegate.
        base.OnMouseHover(e);
    }

    protected override void OnMouseMove(MouseEventArgs e)
    {

        // Make the curser the Hand curser when the mouse moves 
        // over the button.
        Cursor = Cursors.Hand;

        // Call MyBase.OnMouseHover to activate the delegate.
        base.OnMouseHover(e);
    }

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

Control Class | Control Members | System.Windows.Forms Namespace | MouseHover

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