TabControl.DrawItem Evento

Definizione

Spazio dei nomi:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Origine:

TabControl.cs

Si verifica quando l'oggetto TabControl deve disegnare ognuna delle relative schede se la DrawMode proprietà è impostata su OwnerDrawFixed.

public:
 event System::Windows::Forms::DrawItemEventHandler ^ DrawItem;

public event System.Windows.Forms.DrawItemEventHandler? DrawItem;

member this.DrawItem : System.Windows.Forms.DrawItemEventHandler 

Public Custom Event DrawItem As DrawItemEventHandler 

Tipo evento

DrawItemEventHandler

Esempio

Nell'esempio di codice seguente viene creato un oggetto TabControl con un oggetto TabPage. In questo esempio viene dichiarato un gestore eventi utilizzato per disegnare una stringa e Rectangle nella scheda di tabPage1. Il gestore eventi è associato all'evento DrawItem .

using namespace System::Drawing;
using namespace System::Windows::Forms;
public ref class Form1: public Form
{
private:
   Rectangle tabArea;
   RectangleF tabTextArea;

public:
   Form1()
   {
      TabControl^ tabControl1 = gcnew TabControl;
      TabPage^ tabPage1 = gcnew TabPage;
      
      // Allows access to the DrawItem event.
      tabControl1->DrawMode = TabDrawMode::OwnerDrawFixed;
      tabControl1->SizeMode = TabSizeMode::Fixed;
      tabControl1->Controls->Add( tabPage1 );
      tabControl1->ItemSize = System::Drawing::Size( 80, 30 );
      tabControl1->Location = Point(25,25);
      tabControl1->Size = System::Drawing::Size( 250, 250 );
      tabPage1->TabIndex = 0;
      ClientSize = System::Drawing::Size( 300, 300 );
      Controls->Add( tabControl1 );
      tabArea = tabControl1->GetTabRect( 0 );
      tabTextArea = tabControl1->GetTabRect( 0 );
      
      // Binds the event handler DrawOnTab to the DrawItem event
      // through the DrawItemEventHandler delegate.
      tabControl1->DrawItem += gcnew DrawItemEventHandler( this, &Form1::DrawOnTab );
   }


private:

   // Declares the event handler DrawOnTab which is a method that
   // draws a String* and Rectangle on the tabPage1 tab.
   void DrawOnTab( Object^ /*sender*/, DrawItemEventArgs^ e )
   {
      Graphics^ g = e->Graphics;
      Pen^ p = gcnew Pen( Color::Blue );
      System::Drawing::Font^ font = gcnew System::Drawing::Font( "Arial",10.0f );
      SolidBrush^ brush = gcnew SolidBrush( Color::Red );
      g->DrawRectangle( p, tabArea );
      g->DrawString( "tabPage1", font, brush, tabTextArea );
   }

};

int main()
{
   Application::Run( gcnew Form1 );
}

using System.Drawing;
using System.Windows.Forms;

public class Form1 : Form
{
    private Rectangle tabArea;
    private RectangleF tabTextArea;

    public Form1()
    {
        TabControl tabControl1 = new TabControl();
        TabPage tabPage1 = new TabPage();

        // Allows access to the DrawItem event. 
        tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;

        tabControl1.SizeMode = TabSizeMode.Fixed;
        tabControl1.Controls.Add(tabPage1);
        tabControl1.ItemSize = new Size(80, 30);
        tabControl1.Location = new Point(25, 25);
        tabControl1.Size = new Size(250, 250);
        tabPage1.TabIndex = 0;
        ClientSize = new Size(300, 300);
        Controls.Add(tabControl1);

        tabArea = tabControl1.GetTabRect(0);
        tabTextArea = (RectangleF)tabControl1.GetTabRect(0);

        // Binds the event handler DrawOnTab to the DrawItem event 
        // through the DrawItemEventHandler delegate.
        tabControl1.DrawItem += new DrawItemEventHandler(DrawOnTab);
    }

    // Declares the event handler DrawOnTab which is a method that
    // draws a string and Rectangle on the tabPage1 tab.
    private void DrawOnTab(object sender, DrawItemEventArgs e)
    {
        Graphics g = e.Graphics;
        Pen p = new Pen(Color.Blue);
        Font font = new Font("Arial", 10.0f);
        SolidBrush brush = new SolidBrush(Color.Red);

        g.DrawRectangle(p, tabArea);
        g.DrawString("tabPage1", font, brush, tabTextArea);
    }

    static void Main() 
    {
        Application.Run(new Form1());
    }
}

Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
    Inherits Form
    Private tabArea As Rectangle
    Private tabTextArea As RectangleF

    Public Sub New()
        Dim tabControl1 As New TabControl()
        Dim tabPage1 As New TabPage()

        ' Allows access to the DrawItem event. 
        tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed

        tabControl1.SizeMode = TabSizeMode.Fixed
        tabControl1.Controls.Add(tabPage1)
        tabControl1.ItemSize = New Size(80, 30)
        tabControl1.Location = New Point(25, 25)
        tabControl1.Size = New Size(250, 250)
        tabPage1.TabIndex = 0
        ClientSize = New Size(300, 300)
        Controls.Add(tabControl1)

        tabArea = tabControl1.GetTabRect(0)
        tabTextArea = RectangleF.op_Implicit(tabControl1.GetTabRect(0))

        ' Binds the event handler DrawOnTab to the DrawItem event 
        ' through the DrawItemEventHandler delegate.
        AddHandler tabControl1.DrawItem, AddressOf DrawOnTab
    End Sub

    ' Declares the event handler DrawOnTab which is a method that
    ' draws a string and Rectangle on the tabPage1 tab.
    Private Sub DrawOnTab(ByVal sender As Object, ByVal e As DrawItemEventArgs)
        Dim g As Graphics = e.Graphics
        Dim p As New Pen(Color.Blue)
        Dim font As New Font("Arial", 10.0F)
        Dim brush As New SolidBrush(Color.Red)

        g.DrawRectangle(p, tabArea)
        g.DrawString("tabPage1", font, brush, tabTextArea)
    End Sub

    Shared Sub Main()
        Application.Run(New Form1())
    End Sub
End Class

Commenti

Quando si imposta la DrawMode proprietà su OwnerDrawFixed, TabControl genera l'evento DrawItem ogni volta che deve disegnare una delle relative schede. Per personalizzare l'aspetto delle schede, specificare il codice di disegno personalizzato in un gestore per l'evento DrawItem .

Non TabControl supporta le dimensioni delle schede variabili con disegno proprietario.

Per ulteriori informazioni sulla gestione degli eventi, consultare gestione e generazione di eventi.

Vedi anche

• DrawItemEventHandler
• OnDrawItem(DrawItemEventArgs)