StatusBarDrawItemEventHandler Delegato

Riferimento

Definizione

Spazio dei nomi:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Importante

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Rappresenta il metodo che gestirà l'evento DrawItem di un oggetto StatusBar.

public delegate void StatusBarDrawItemEventHandler(System::Object ^ sender, StatusBarDrawItemEventArgs ^ sbdevent);

public delegate void StatusBarDrawItemEventHandler(object sender, StatusBarDrawItemEventArgs sbdevent);

type StatusBarDrawItemEventHandler = delegate of obj * StatusBarDrawItemEventArgs -> unit

Public Delegate Sub StatusBarDrawItemEventHandler(sender As Object, sbdevent As StatusBarDrawItemEventArgs)

Parametri

sender: Object

Origine dell'evento.

sbdevent: StatusBarDrawItemEventArgs

Oggetto StatusBarDrawItemEventArgs che contiene i dati dell'evento.

Esempio

Nell'esempio di codice seguente viene illustrato come usare la StatusBarPanel.Style proprietà, il StatusBarDrawItemEventHandler delegato, la StatusBarDrawItemEventArgs classe, l'enumerazione e la StatusBarPanelStyle Panel proprietà. Per eseguire l'esempio, incollare il codice seguente in un modulo. Chiamare il InitializeStatusBarPanels metodo nel costruttore del modulo o Load nel metodo di gestione degli eventi.

StatusBar^ StatusBar1;
void InitializeStatusBarPanels()
{
   StatusBar1 = gcnew StatusBar;
   
   // Create two StatusBarPanel objects.
   StatusBarPanel^ panel1 = gcnew StatusBarPanel;
   StatusBarPanel^ panel2 = gcnew StatusBarPanel;
   
   // Set the style of the panels.  
   // panel1 will be owner-drawn.
   panel1->Style = StatusBarPanelStyle::OwnerDraw;
   
   // The panel2 object will be drawn by the operating system.
   panel2->Style = StatusBarPanelStyle::Text;
   
   // Set the text of both panels to the same date string.
   panel1->Text = System::DateTime::Today.ToShortDateString();
   panel2->Text = System::DateTime::Today.ToShortDateString();
   
   // Add both panels to the StatusBar.
   StatusBar1->Panels->Add( panel1 );
   StatusBar1->Panels->Add( panel2 );
   
   // Make panels visible by setting the ShowPanels 
   // property to True.
   StatusBar1->ShowPanels = true;
   
   // Associate the event-handling method with the DrawItem event 
   // for the owner-drawn panel.
   StatusBar1->DrawItem += gcnew StatusBarDrawItemEventHandler( this, &Form1::DrawCustomStatusBarPanel );
   this->Controls->Add( StatusBar1 );
}


// Draw the panel.
void DrawCustomStatusBarPanel( Object^ sender, StatusBarDrawItemEventArgs^ e )
{
   
   // Draw a blue background in the owner-drawn panel.
   e->Graphics->FillRectangle( Brushes::AliceBlue, e->Bounds );
   
   // Create a StringFormat object to align text in the panel.
   StringFormat^ textFormat = gcnew StringFormat;
   
   // Center the text in the middle of the line.
   textFormat->LineAlignment = StringAlignment::Center;
   
   // Align the text to the left.
   textFormat->Alignment = StringAlignment::Far;
   
   // Draw the panel's text in dark blue using the Panel 
   // and Bounds properties of the StatusBarEventArgs object 
   // and the StringFormat object.
   e->Graphics->DrawString( e->Panel->Text, StatusBar1->Font, Brushes::DarkBlue, RectangleF(e->Bounds.X,e->Bounds.Y,e->Bounds.Width,e->Bounds.Height), textFormat );
}

private StatusBar StatusBar1;

private void InitializeStatusBarPanels()
{
    StatusBar1 = new StatusBar();

    // Create two StatusBarPanel objects.
    StatusBarPanel panel1 = new StatusBarPanel();
    StatusBarPanel panel2 = new StatusBarPanel();

    // Set the style of the panels.  
    // panel1 will be owner-drawn.
    panel1.Style = StatusBarPanelStyle.OwnerDraw;

    // The panel2 object will be drawn by the operating system.
    panel2.Style = StatusBarPanelStyle.Text;

    // Set the text of both panels to the same date string.
    panel1.Text = System.DateTime.Today.ToShortDateString();
    panel2.Text = System.DateTime.Today.ToShortDateString();

    // Add both panels to the StatusBar.
    StatusBar1.Panels.Add(panel1);
    StatusBar1.Panels.Add(panel2);

    // Make panels visible by setting the ShowPanels 
    // property to True.
    StatusBar1.ShowPanels = true;

    // Associate the event-handling method with the DrawItem event 
    // for the owner-drawn panel.
    StatusBar1.DrawItem += 
        new StatusBarDrawItemEventHandler(DrawCustomStatusBarPanel);
        
    this.Controls.Add(StatusBar1);
}

// Draw the panel.
private void DrawCustomStatusBarPanel(object sender, 
    StatusBarDrawItemEventArgs e)
{

    // Draw a blue background in the owner-drawn panel.
    e.Graphics.FillRectangle(Brushes.AliceBlue, e.Bounds);

    // Create a StringFormat object to align text in the panel.
    StringFormat textFormat = new StringFormat();

    // Center the text in the middle of the line.
    textFormat.LineAlignment = StringAlignment.Center;

    // Align the text to the left.
    textFormat.Alignment = StringAlignment.Far;

    // Draw the panel's text in dark blue using the Panel 
    // and Bounds properties of the StatusBarEventArgs object 
    // and the StringFormat object.
    e.Graphics.DrawString(e.Panel.Text, StatusBar1.Font, 
        Brushes.DarkBlue, new RectangleF(e.Bounds.X, 
        e.Bounds.Y, e.Bounds.Width, e.Bounds.Height), textFormat);
}

Private StatusBar1 As StatusBar

Private Sub InitializeStatusBarPanels()
    StatusBar1 = New StatusBar

    ' Create two StatusBarPanel objects.
    Dim panel1 As New StatusBarPanel
    Dim panel2 As New StatusBarPanel

    ' Set the style of the panels.  
    ' panel1 will be owner-drawn.
    panel1.Style = StatusBarPanelStyle.OwnerDraw

    ' The panel2 object will be drawn by the operating system.
    panel2.Style = StatusBarPanelStyle.Text

    ' Set the text of both panels to the same date string.
    panel1.Text = DateTime.Today.ToShortDateString()
    panel2.Text = DateTime.Today.ToShortDateString()

    ' Add both panels to the StatusBar.
    StatusBar1.Panels.Add(panel1)
    StatusBar1.Panels.Add(panel2)

    ' Make panels visible by setting the ShowPanels 
    ' property to True.
    StatusBar1.ShowPanels = True

    ' Use the AddHandler syntax to handle the DrawItem event
    ' for the owner-drawn panel.
    AddHandler StatusBar1.DrawItem, _
        New StatusBarDrawItemEventHandler( _
        AddressOf DrawCustomStatusBarPanel)
    Me.Controls.Add(StatusBar1)
End Sub

' Draw the panel.
Private Sub DrawCustomStatusBarPanel(ByVal sender As Object, _
    ByVal e As StatusBarDrawItemEventArgs)

    ' Draw a blue background in the owner-drawn panel.
    e.Graphics.FillRectangle(Brushes.AliceBlue, e.Bounds)

    ' Create a StringFormat object to align text in the panel.
    Dim textFormat As New StringFormat

    ' Center the text in the middle of the line.
    textFormat.LineAlignment = StringAlignment.Center

    ' Align the text to the left.
    textFormat.Alignment = StringAlignment.Far

    ' Draw the panel's text in dark blue using the Panel 
    ' and Bounds properties of the StatusBarEventArgs object 
    ' and the StringFormat object.
    e.Graphics.DrawString(e.Panel.Text, StatusBar1.Font, _
          Brushes.DarkBlue, New RectangleF(e.Bounds.X, e.Bounds.Y, _
          e.Bounds.Width, e.Bounds.Height), textFormat)

End Sub

Commenti

Quando si crea un delegato StatusBarDrawItemEventHandler, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato. Per altre informazioni sui delegati del gestore eventi, vedere Gestione e generazione di eventi.

Metodi di estensione

GetMethodInfo(Delegate)

Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato.

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