TrackBarRenderer.DrawTopPointingThumb Método

Definição

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Origem:

TrackBarRenderer.cs

Desenha um controle deslizante de barra de faixa para cima (também conhecido como o polegar) com estilos visuais.

public:
 static void DrawTopPointingThumb(System::Drawing::Graphics ^ g, System::Drawing::Rectangle bounds, System::Windows::Forms::VisualStyles::TrackBarThumbState state);

public static void DrawTopPointingThumb(System.Drawing.Graphics g, System.Drawing.Rectangle bounds, System.Windows.Forms.VisualStyles.TrackBarThumbState state);

static member DrawTopPointingThumb : System.Drawing.Graphics * System.Drawing.Rectangle * System.Windows.Forms.VisualStyles.TrackBarThumbState -> unit

Public Shared Sub DrawTopPointingThumb (g As Graphics, bounds As Rectangle, state As TrackBarThumbState)

Parâmetros

g

Graphics

O Graphics usado para desenhar o controle deslizante da barra de faixa.

bounds

Rectangle

O Rectangle que especifica os limites do controle deslizante da barra de faixa.

state

TrackBarThumbState

Um dos TrackBarThumbState valores que especifica o estado visual do controle deslizante da barra de faixa.

Exceções

InvalidOperationException

O sistema operacional não dá suporte a estilos visuais.

- ou -

Os estilos visuais são desabilitados pelo usuário no sistema operacional.

- ou -

Os estilos visuais não são aplicados à área do cliente das janelas do aplicativo.

Exemplos

O exemplo de código a seguir usa o DrawTopPointingThumb método em um método de OnPaint controle personalizado para desenhar um controle deslizante de barra de faixa apontando para cima. Este exemplo de código faz parte de um exemplo maior fornecido para a TrackBarRenderer classe.

    // Draw the track bar.
protected:
    virtual void OnPaint(PaintEventArgs^ e) override
    {
        if (!TrackBarRenderer::IsSupported)
        {
            this->Parent->Text = "CustomTrackBar Disabled";
            return;
        }

        this->Parent->Text = "CustomTrackBar Enabled";
        TrackBarRenderer::DrawHorizontalTrack(e->Graphics,
            trackRectangle);
        TrackBarRenderer::DrawTopPointingThumb(e->Graphics,
            thumbRectangle, thumbState);
        TrackBarRenderer::DrawHorizontalTicks(e->Graphics,
            ticksRectangle, numberTicks, EdgeStyle::Raised);
    }

    // Determine whether the user has clicked the track bar thumb.
protected:
    virtual void OnMouseDown(MouseEventArgs^ e) override
    {
        if (!TrackBarRenderer::IsSupported)
        {
            return;
        }
        if (this->thumbRectangle.Contains(e->Location))
        {
            thumbClicked = true;
            thumbState = TrackBarThumbState::Pressed;
        }

        this->Invalidate();
    }

// Draw the track bar.
protected override void OnPaint(PaintEventArgs e)
{
    if (!TrackBarRenderer.IsSupported)
    {
        this.Parent.Text = "CustomTrackBar Disabled";
        return;
    }

    this.Parent.Text = "CustomTrackBar Enabled";
    TrackBarRenderer.DrawHorizontalTrack(e.Graphics,
        trackRectangle);
    TrackBarRenderer.DrawTopPointingThumb(e.Graphics,
        thumbRectangle, thumbState);
    TrackBarRenderer.DrawHorizontalTicks(e.Graphics,
        ticksRectangle, numberTicks, EdgeStyle.Raised);
}

// Determine whether the user has clicked the track bar thumb.
protected override void OnMouseDown(MouseEventArgs e)
{
    if (!TrackBarRenderer.IsSupported)
        return;

    if (this.thumbRectangle.Contains(e.Location))
    {
        thumbClicked = true;
        thumbState = TrackBarThumbState.Pressed;
    }

    this.Invalidate();
}

' Draw the track bar.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
    If Not TrackBarRenderer.IsSupported Then
        Me.Parent.Text = "CustomTrackBar Disabled"
        Return
    End If

    Me.Parent.Text = "CustomTrackBar Enabled"
    TrackBarRenderer.DrawHorizontalTrack(e.Graphics, _
        trackRectangle)
    TrackBarRenderer.DrawTopPointingThumb(e.Graphics, _
        thumbRectangle, thumbState)
    TrackBarRenderer.DrawHorizontalTicks(e.Graphics, _
        ticksRectangle, numberTicks, EdgeStyle.Raised)
End Sub

' Determine whether the user has clicked the track bar thumb.
Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
    If Not TrackBarRenderer.IsSupported Then
        Return
    End If
    If Me.thumbRectangle.Contains(e.Location) Then
        thumbClicked = True
        thumbState = TrackBarThumbState.Pressed
    End If

    Me.Invalidate()
End Sub

Comentários

Antes de chamar esse método, você deve verificar se o valor da IsSupported propriedade é true.