Evento Shape.MouseDown

Articolo
10/30/2012

Si verifica quando il puntatore del mouse viene posizionato sopra la forma e si preme un pulsante del mouse.

Spazio dei nomi: Microsoft.VisualBasic.PowerPacks
Assembly: Microsoft.VisualBasic.PowerPacks.Vs (in Microsoft.VisualBasic.PowerPacks.Vs.dll)

Sintassi

'Dichiarazione
<BrowsableAttribute(True)> _
Public Event MouseDown As MouseEventHandler

[BrowsableAttribute(true)]
public event MouseEventHandler MouseDown

[BrowsableAttribute(true)]
public:
 event MouseEventHandler^ MouseDown {
    void add (MouseEventHandler^ value);
    void remove (MouseEventHandler^ value);
}

[<BrowsableAttribute(true)>]
member MouseDown : IEvent<MouseEventHandler,
    MouseEventArgs>

JScript non supporta gli eventi.

Note

Gli eventi del mouse si verificano nel seguente ordine:

MouseEnter

MouseMove

MouseHover / MouseDown / MouseWheel

MouseUp

MouseLeave

per ulteriori informazioni su come gestire gli eventi, vedere Utilizzo degli eventi.

Esempi

Nell'esempio seguente viene illustrato come utilizzare MouseDown, MouseMovee MouseUp eventi per disegnare righe in una classe RectangleShape controllare.Questo esempio presuppone che l'utente abbia a RectangleShape controllare RectangleShape2 denominato in un form.

Private mousePath = New System.Drawing.Drawing2D.GraphicsPath()

Private Sub RectangleShape2_MouseDown(
    ByVal sender As Object, 
     ByVal e As System.Windows.Forms.MouseEventArgs
  ) Handles RectangleShape2.MouseDown

    Dim mouseDownLocation As New Point(e.X + RectangleShape2.Left, 
      e.Y + RectangleShape2.Top)
    ' Clear the previous line.
    mousePath.Dispose()
    mousePath = New System.Drawing.Drawing2D.GraphicsPath()
    RectangleShape2.Invalidate()
    ' Add a line to the graphics path.
    mousePath.AddLine(mouseDownLocation, mouseDownLocation)
End Sub

Private Sub RectangleShape2_MouseMove(
    ByVal sender As Object, 
    ByVal e As System.Windows.Forms.MouseEventArgs
  ) Handles RectangleShape2.MouseMove

    Dim mouseX As Integer = e.X + RectangleShape2.Left
    Dim mouseY As Integer = e.Y + RectangleShape2.Top
    ' Add a line to the graphics path.
    mousePath.AddLine(mouseX, mouseY, mouseX, mouseY)
End Sub

Private Sub RectangleShape2_MouseUp(
    ByVal sender As Object, 
    ByVal e As System.Windows.Forms.MouseEventArgs
  ) Handles RectangleShape2.MouseUp

    Dim mouseUpLocation = New System.Drawing.Point(e.X + 
      RectangleShape2.Left, e.Y + RectangleShape2.Top)
    ' Add a line to the graphics path.
    mousePath.Addline(mouseUpLocation, mouseUpLocation)
    ' Force the shape to redraw.
    RectangleShape2.Invalidate()
End Sub

Private Sub RectangleShape2_Paint(
    ByVal sender As Object, 
    ByVal e As System.Windows.Forms.PaintEventArgs
  ) Handles RectangleShape2.Paint

    ' Draw the line.
    e.Graphics.DrawPath(System.Drawing.Pens.DarkRed, mousePath)
End Sub

private System.Drawing.Drawing2D.GraphicsPath mousePath = 
    new System.Drawing.Drawing2D.GraphicsPath();

private void rectangleShape2_MouseDown(object sender, 
    System.Windows.Forms.MouseEventArgs e)
{
    Point mouseDownLocation = new Point(e.X + rectangleShape2.Left, 
        e.Y + rectangleShape2.Top);
    // Clear the previous line.
    mousePath.Dispose();
    mousePath = new System.Drawing.Drawing2D.GraphicsPath();
    rectangleShape2.Invalidate();
    // Add a line to the graphics path.
    mousePath.AddLine(mouseDownLocation, mouseDownLocation);
}

private void rectangleShape2_MouseMove(object sender, 
    System.Windows.Forms.MouseEventArgs e)
{
    int mouseX = e.X + rectangleShape2.Left;
    int mouseY = e.Y + rectangleShape2.Top;
    // Add a line to the graphics path.
    mousePath.AddLine(mouseX, mouseY, mouseX, mouseY);
}

private void rectangleShape2_MouseUp(object sender, 
    System.Windows.Forms.MouseEventArgs e)
{
    System.Drawing.Point mouseUpLocation = 
        new System.Drawing.Point(e.X + rectangleShape2.Left, 
            e.Y + rectangleShape2.Top);
    // Add a line to the graphics path.
    mousePath.AddLine(mouseUpLocation, mouseUpLocation);
    // Force the shape to redraw.
    rectangleShape2.Invalidate();
}

private void rectangleShape2_Paint(object sender, 
    System.Windows.Forms.PaintEventArgs e)
{
    // Draw the line.
    e.Graphics.DrawPath(System.Drawing.Pens.DarkRed, mousePath);
}

Sicurezza di .NET Framework

Attendibilità totale per il chiamante immediato. Impossibile utilizzare questo membro in codice parzialmente attendibile. Per ulteriori informazioni, vedere Utilizzo di librerie da codice parzialmente attendibile.