PaintEventArgs.Graphics-Eigenschaft

Ruft die zum Zeichnen verwendete Grafik ab.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

Syntax

'Declaration
Public ReadOnly Property Graphics As Graphics
'Usage
Dim instance As PaintEventArgs
Dim value As Graphics

value = instance.Graphics

public Graphics Graphics { get; }

public:
property Graphics^ Graphics {
    Graphics^ get ();
}

/** @property */
public Graphics get_Graphics ()

public function get Graphics () : Graphics

Eigenschaftenwert

Das zum Zeichnen verwendete Graphics-Objekt. Das Graphics-Objekt stellt Methoden für das Zeichnen von Objekten auf dem Anzeigegerät bereit.

Beispiel

Im folgenden Beispiel wird veranschaulicht, wie das Paint-Ereignis behandelt und die PaintEventArgs-Klasse verwendet wird, um im Formular Rechtecke zu zeichnen. Das MouseDown-Ereignis und das MouseUp-Ereignis werden behandelt, um die Größe des Rechtecks zu bestimmen. Im Beispiel wird außerdem veranschaulicht, wie mithilfe der Invalidate-Methode der Bereich des Rechtecks für ungültig erklärt und dadurch das Neuzeichnen erzwungen wird.

Dim RcDraw As Rectangle
Dim PenWidth As Integer = 5


Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown

    ' Determine the initial rectangle coordinates...

    RcDraw.X = e.X
    RcDraw.Y = e.Y

End Sub

Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp

    ' Determine the width and height of the rectangle...

    If e.X < RcDraw.X Then
        RcDraw.Width = RcDraw.X - e.X
        RcDraw.X = e.X
    Else
        RcDraw.Width = e.X - RcDraw.X
    End If

    If e.Y < RcDraw.Y Then
        RcDraw.Height = RcDraw.Y - e.Y
        RcDraw.Y = e.Y
    Else
        RcDraw.Height = e.Y - RcDraw.Y
    End If

    ' Force a repaint of the region occupied by the rectangle...

    Me.Invalidate(RcDraw)

End Sub

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint

    ' Draw the rectangle...

    e.Graphics.DrawRectangle(New Pen(Color.Blue, PenWidth), RcDraw)

End Sub

private Rectangle RcDraw;
private float PenWidth = 5;

private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{

    // Determine the initial rectangle coordinates...

    RcDraw.X = e.X;
    RcDraw.Y = e.Y;

}

private void Form1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
{

    // Determine the width and height of the rectangle...

    if(e.X < RcDraw.X)
    {
        RcDraw.Width = RcDraw.X - e.X;
        RcDraw.X = e.X;
    }
    else
    {
        RcDraw.Width = e.X - RcDraw.X;
    }

    if(e.Y < RcDraw.Y)
    {
        RcDraw.Height = RcDraw.Y - e.Y;
        RcDraw.Y = e.Y;
    }
    else
    {
        RcDraw.Height = e.Y - RcDraw.Y;
    }

    // Force a repaint of the region occupied by the rectangle...

    this.Invalidate(RcDraw);

}

private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{

    // Draw the rectangle...

    e.Graphics.DrawRectangle(new Pen(Color.Blue, PenWidth), RcDraw);
    
}

private:
   Rectangle RcDraw;
   void Form1_MouseDown( Object^ /*sender*/, System::Windows::Forms::MouseEventArgs^ e )
   {
      // Determine the initial rectangle coordinates...
      RcDraw.X = e->X;
      RcDraw.Y = e->Y;
   }

   void Form1_MouseUp( Object^ /*sender*/, System::Windows::Forms::MouseEventArgs^ e )
   {
      // Determine the width and height of the rectangle...
      if ( e->X < RcDraw.X )
      {
         RcDraw.Width = RcDraw.X - e->X;
         RcDraw.X = e->X;
      }
      else
      {
         RcDraw.Width = e->X - RcDraw.X;
      }

      if ( e->Y < RcDraw.Y )
      {
         RcDraw.Height = RcDraw.Y - e->Y;
         RcDraw.Y = e->Y;
      }
      else
      {
         RcDraw.Height = e->Y - RcDraw.Y;
      }

      // Force a repaint of the region occupied by the rectangle...
      this->Invalidate( RcDraw );
   }

   void Form1_Paint( Object^ /*sender*/, System::Windows::Forms::PaintEventArgs^ e )
   {
      // Draw the rectangle...
      float PenWidth = 5;
      e->Graphics->DrawRectangle( gcnew Pen( Color::Blue,PenWidth ), RcDraw );
   }

private Rectangle rcDraw;

private float penWidth = 5;

private void Form1_MouseDown(Object sender,
    System.Windows.Forms.MouseEventArgs e)
{
    // Determine the initial rectangle coordinates...
    rcDraw.set_X(e.get_X());
    rcDraw.set_Y(e.get_Y());
} //Form1_MouseDown

private void Form1_MouseUp(Object sender, 
    System.Windows.Forms.MouseEventArgs e)
{
    // Determine the width and height of the rectangle...
    if (e.get_X() < rcDraw.get_X()) {
        rcDraw.set_Width(rcDraw.get_X() - e.get_X());
        rcDraw.set_X(e.get_X());
    }
    else {
        rcDraw.set_Width(e.get_X() - rcDraw.get_X());
    }

    if (e.get_Y() < rcDraw.get_Y()) {
        rcDraw.set_Height(rcDraw.get_Y() - e.get_Y());
        rcDraw.set_Y(e.get_Y());
    }
    else {
        rcDraw.set_Height(e.get_Y() - rcDraw.get_Y());
    }

    // Force a repaint of the region occupied by the rectangle...
    this.Invalidate(rcDraw);
} //Form1_MouseUp

private void Form1_Paint(Object sender,
    System.Windows.Forms.PaintEventArgs e)
{
    // Draw the rectangle...
    e.get_Graphics().DrawRectangle(new Pen(Color.get_Blue(), 
        penWidth), rcDraw);
} //Form1_Paint

' This example creates a PictureBox control on the form and draws to it. 
' This example assumes that the Form_Load event handler method is connected 
' to the Load event of the form.
Private pictureBox1 As New PictureBox()

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ' Dock the PictureBox to the form and set its background to white.
    pictureBox1.Dock = DockStyle.Fill
    pictureBox1.BackColor = Color.White
    ' Connect the Paint event of the PictureBox to the event handler method.
    AddHandler pictureBox1.Paint, AddressOf Me.pictureBox1_Paint

    ' Add the PictureBox control to the Form.
    Me.Controls.Add(pictureBox1)
End Sub 'Form1_Load


Private Sub pictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs)
    ' Create a local version of the graphics object for the PictureBox.
    Dim g As Graphics = e.Graphics

    ' Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control", _
        New Font("Arial", 10), Brushes.Red, New PointF(30.0F, 30.0F))
    ' Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.Red, pictureBox1.Left, _ 
        pictureBox1.Top, pictureBox1.Right, pictureBox1.Bottom)
End Sub 'pictureBox1_Paint

// This example creates a PictureBox control on the form and draws to it.
// This example assumes that the Form_Load event handler method is
// connected to the Load event of the form.

private PictureBox pictureBox1 = new PictureBox();
private void Form1_Load(object sender, System.EventArgs e)
{
    // Dock the PictureBox to the form and set its background to white.
    pictureBox1.Dock = DockStyle.Fill;
    pictureBox1.BackColor = Color.White;
    // Connect the Paint event of the PictureBox to the event handler method.
    pictureBox1.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox1_Paint);

    // Add the PictureBox control to the Form.
    this.Controls.Add(pictureBox1);
}

private void pictureBox1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
    // Create a local version of the graphics object for the PictureBox.
    Graphics g = e.Graphics;

    // Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control",
        new Font("Arial",10), System.Drawing.Brushes.Blue, new Point(30,30));
    // Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.Red, pictureBox1.Left, pictureBox1.Top,
        pictureBox1.Right, pictureBox1.Bottom);
}

   // This example creates a PictureBox control on the form and draws to it.
   // This example assumes that the Form_Load event handler method is
   // connected to the Load event of the form.
private:
   PictureBox^ pictureBox1;
   void Form1_Load( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      pictureBox1 = gcnew PictureBox;

      // Dock the PictureBox to the form and set its background to white.
      pictureBox1->Dock = DockStyle::Fill;
      pictureBox1->BackColor = Color::White;

      // Connect the Paint event of the PictureBox to the event handler method.
      pictureBox1->Paint += gcnew System::Windows::Forms::PaintEventHandler( this, &Form1::pictureBox1_Paint );

      // Add the PictureBox control to the Form.
      this->Controls->Add( pictureBox1 );
   }

   void pictureBox1_Paint( Object^ /*sender*/, System::Windows::Forms::PaintEventArgs^ e )
   {
      // Create a local version of the graphics object for the PictureBox.
      Graphics^ g = e->Graphics;

      // Draw a string on the PictureBox.
      g->DrawString( "This is a diagonal line drawn on the control",
         gcnew System::Drawing::Font( "Arial",10 ), System::Drawing::Brushes::Blue, Point(30,30) );

      // Draw a line in the PictureBox.
      g->DrawLine( System::Drawing::Pens::Red, pictureBox1->Left, pictureBox1->Top,
         pictureBox1->Right, pictureBox1->Bottom );
   }

// This example creates a PictureBox control on the form and draws to it.
// This example assumes that the Form_Load event handler method is
// connected to the Load event of the form.
private PictureBox pictureBox1 = new PictureBox();

private void Form1_Load(Object sender, System.EventArgs e)
{
    // Dock the PictureBox to the form and set its background to white.
    pictureBox1.set_Dock(DockStyle.Fill);
    pictureBox1.set_BackColor(Color.get_White());

    // Connect the Paint event of the PictureBox to the event handler 
    // method.
    pictureBox1.add_Paint(new System.Windows.Forms.PaintEventHandler(this.
        pictureBox1_Paint));

    // Add the PictureBox control to the Form.
    this.get_Controls().Add(pictureBox1);
} //Form1_Load

private void pictureBox1_Paint(Object sender, 
    System.Windows.Forms.PaintEventArgs e)
{
    // Create a local version of the graphics object for the PictureBox.
    Graphics g = e.get_Graphics();

    // Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control", 
        new Font("Arial", 10), System.Drawing.Brushes.get_Blue(), 
        (PointF)new PointF(30, 30));

    // Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.get_Red(), pictureBox1.get_Left(), 
        pictureBox1.get_Top(), pictureBox1.get_Right(), 
        pictureBox1.get_Bottom());
} //pictureBox1_Paint

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

.NET Compact Framework

Unterstützt in: 2.0, 1.0

Siehe auch

Referenz

PaintEventArgs-Klasse
PaintEventArgs-Member
System.Windows.Forms-Namespace
Graphics