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MeasureItemEventArgs (Clase)

Proporciona datos para el evento MeasureItem de los controles ListBox, ComboBox, CheckedListBox y MenuItem.

Espacio de nombres: System.Windows.Forms
Ensamblado: System.Windows.Forms (en system.windows.forms.dll)

public class MeasureItemEventArgs : EventArgs
public class MeasureItemEventArgs extends EventArgs
public class MeasureItemEventArgs extends EventArgs
No aplicable.

Este evento se envía cuando la propiedad OwnerDraw de ListBox, ComboBox, CheckedListBox o MenuItem se establece en true. Se utiliza para indicar a la función de dibujo cómo ajustar el tamaño de un elemento.

Para obtener información acerca del modelo de eventos, vea Eventos y delegados.

En el ejemplo de código siguiente se muestra cómo se utiliza la propiedad Graphics para realizar el dibujo personalizado de los elementos de un ListBox.

public class Form1 : System.Windows.Forms.Form
{
   private System.Windows.Forms.ListBox listBox1;
   private System.ComponentModel.Container components = null;


   protected override void Dispose(bool disposing)
   {
      if( disposing )
      {
         if ( components != null ) 
            components.Dispose();

         if ( foreColorBrush != null )
            foreColorBrush.Dispose();
      }
      base.Dispose(disposing);
   }

     #region Windows Form Designer generated code
   /// <summary>
   /// Required method for Designer support - do not modify
   /// the contents of this method with the code editor.
   /// </summary>
   private void InitializeComponent()
   {
      this.listBox1 = new System.Windows.Forms.ListBox();
      this.SuspendLayout();
      // 
      // listBox1
      // 
      this.listBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable;
      this.listBox1.Location = new System.Drawing.Point(16, 48);
      this.listBox1.Name = "listBox1";
      this.listBox1.SelectionMode = System.Windows.Forms.SelectionMode.MultiExtended;
      this.listBox1.Size = new System.Drawing.Size(256, 134);
      this.listBox1.TabIndex = 0;
      this.listBox1.MeasureItem += new System.Windows.Forms.MeasureItemEventHandler(this.listBox1_MeasureItem);
      this.listBox1.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.listBox1_DrawItem);
      // 
      // Form1
      // 
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                   this.listBox1});
      this.Name = "Form1";
      this.Text = "Form1";
      this.ResumeLayout(false);

   }
     #endregion

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

   private void listBox1_MeasureItem(object sender, System.Windows.Forms.MeasureItemEventArgs e)
   {
      Font font = ((ListBoxFontItem)listBox1.Items[e.Index]).Font;
      SizeF stringSize = e.Graphics.MeasureString(font.Name, font);

      // Set the height and width of the item
      e.ItemHeight = (int)stringSize.Height;
      e.ItemWidth = (int)stringSize.Width;
   }

   // For efficiency, cache the brush to use for drawing.
   private SolidBrush foreColorBrush;

   private void listBox1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
   {
      Brush brush;

      // Create the brush using the ForeColor specified by the DrawItemEventArgs
      if ( foreColorBrush == null )
         foreColorBrush = new SolidBrush(e.ForeColor);
      else if ( foreColorBrush.Color != e.ForeColor )
      {
         // The control's ForeColor has changed, so dispose of the cached brush and
         // create a new one.
         foreColorBrush.Dispose();
         foreColorBrush = new SolidBrush(e.ForeColor);
      }

      // Select the appropriate brush depending on if the item is selected.
      // Since State can be a combinateion (bit-flag) of enum values, you can't use
      // "==" to compare them.
      if ( (e.State & DrawItemState.Selected) == DrawItemState.Selected )
         brush = SystemBrushes.HighlightText;
      else
         brush = foreColorBrush;

      // Perform the painting.
      Font font = ((ListBoxFontItem)listBox1.Items[e.Index]).Font;
      e.DrawBackground();
      e.Graphics.DrawString(font.Name, font, brush, e.Bounds);
      e.DrawFocusRectangle();
   }

   /// <summary>
   ///  A wrapper class for use with storing Fonts in a ListBox.  Since ListBox uses the
   ///  ToString() of its items for the text it displays, this class is needed to return
   ///  the name of the font, rather than its ToString() value.
   /// </summary>
   public class ListBoxFontItem 
   {
      public Font Font;

      public ListBoxFontItem(Font f) 
      {
         Font = f;
      }

      public override string ToString() 
      {
         return Font.Name;
      }
   }
}

public class Form1 extends System.Windows.Forms.Form
{
    private System.Windows.Forms.ListBox listBox1;
    private System.ComponentModel.Container components = null;

    protected void Dispose(boolean disposing)
    {
        if (disposing) {
            if (components != null) {
                components.Dispose();
            }

            if (foreColorBrush != null) {
                foreColorBrush.Dispose();
            }
        }
        super.Dispose(disposing);
    } //Dispose
      
    #region Windows Form Designer generated code
    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.listBox1 = new System.Windows.Forms.ListBox();
        this.SuspendLayout();
        // 
        // listBox1
        // 
        this.listBox1.set_DrawMode(
            System.Windows.Forms.DrawMode.OwnerDrawVariable);
        this.listBox1.set_Location(new System.Drawing.Point(16, 48));
        this.listBox1.set_Name("listBox1");
        this.listBox1.set_SelectionMode(
            System.Windows.Forms.SelectionMode.MultiExtended);
        this.listBox1.set_Size(new System.Drawing.Size(256, 134));
        this.listBox1.set_TabIndex(0);
        this.listBox1.add_MeasureItem(
            new System.Windows.Forms.MeasureItemEventHandler(
            this.listBox1_MeasureItem));
        this.listBox1.add_DrawItem(
            new System.Windows.Forms.DrawItemEventHandler(
            this.listBox1_DrawItem));
        // 
        // Form1
        // 
        this.set_ClientSize(new System.Drawing.Size(292, 273));
        this.get_Controls().AddRange(new System.Windows.Forms.Control[] 
            { this.listBox1 });
        this.set_Name("Form1");
        this.set_Text("Form1");
        this.ResumeLayout(false);
    } //InitializeComponent
    #endregion
      
    /** @attribute STAThread()
     */
    public static void main(String[] args)
    {
        Application.Run(new Form1());
    } //main

    private void listBox1_MeasureItem(Object sender, 
        System.Windows.Forms.MeasureItemEventArgs e)
    {
        Font font = ((ListBoxFontItem)listBox1.get_Items().
             get_Item(e.get_Index())).font;
        SizeF stringSize = 
            e.get_Graphics().MeasureString(font.get_Name(), font);

        // Set the height and width of the item
        e.set_ItemHeight((int)stringSize.get_Height());
        e.set_ItemWidth((int)stringSize.get_Width());
    } //listBox1_MeasureItem

    // For efficiency, cache the brush to use for drawing.
    private SolidBrush foreColorBrush;

    private void listBox1_DrawItem(Object sender, 
        System.Windows.Forms.DrawItemEventArgs e)
    {
        Brush brush;

        // Create the brush using the ForeColor specified by the 
        // DrawItemEventArgs
        if (foreColorBrush == null) {
            foreColorBrush = new SolidBrush(e.get_ForeColor());
        }
        else {
            if (!foreColorBrush.get_Color().Equals(e.get_ForeColor())) {
                // The control's ForeColor has changed, 
                // so dispose of the cached brush and
                // create a new one.
                foreColorBrush.Dispose();
                foreColorBrush = new SolidBrush(e.get_ForeColor());
            }
        }
        // Select the appropriate brush depending on if the item is selected.
        // Since State can be a combinateion (bit-flag) of enum values,
        // you can't use "==" to compare them.
        if ((e.get_State() & DrawItemState.Selected).
            Equals(DrawItemState.Selected)) {
            brush = SystemBrushes.get_HighlightText();
        }
        else {
            brush = foreColorBrush;
        }

        // Perform the painting.
        Font font = ((ListBoxFontItem)listBox1.get_Items().
            get_Item(e.get_Index())).font;
        e.DrawBackground();
        e.get_Graphics().DrawString(font.get_Name(), font, brush, 
            new PointF((float)e.get_Bounds().get_X(), 
            (float)e.get_Bounds().get_Y()));
        e.DrawFocusRectangle();
    } //listBox1_DrawItem

    /// <summary>
    ///  A wrapper class for use with storing Fonts in a ListBox.  
    ///  Since ListBox uses the ToString() of its items 
    ///  for the text it displays, this class is needed to return
    ///  the name of the font, rather than its ToString() value.
    /// </summary>
    public class ListBoxFontItem
    {
        public Font font;

        public ListBoxFontItem(Font f)
        {
            set_Font(f);
        } //ListBoxFontItem

        public String ToString()
        {
            return get_Font().get_Name();
        } //ToString
    } //ListBoxFontItem
} //Form1

System.Object
   System.EventArgs
    System.Windows.Forms.MeasureItemEventArgs

Los miembros estáticos públicos (Shared en Visual Basic) de este tipo son seguros para la ejecución de subprocesos. No se garantiza que los miembros de instancias sean seguros para la ejecución de subprocesos.

Windows 98, Windows 2000 Service Pack 4, Windows CE, Windows Millennium, Windows Mobile para Pocket PC, Windows Mobile para Smartphone, Windows Server 2003, Windows XP Media Center, Windows XP Professional x64, Windows XP SP2, Windows XP Starter

Microsoft .NET Framework 3.0 es compatible con Windows Vista, Microsoft Windows XP SP2 y Windows Server 2003 SP1.

.NET Framework

Compatible con: 3.0, 2.0, 1.1, 1.0
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