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Classe MeasureItemEventArgs

Fornece dados para o MeasureItem evento da ListBox, ComboBox, CheckedListBox, e MenuItem controles.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (em System.Windows.Forms.dll)
public class MeasureItemEventArgs : EventArgs

Este evento é enviado quando o OwnerDraw propriedade de ListBox, ComboBox, CheckedListBox, ou MenuItem é definido como true. Ele é usado para informar a função de desenho como dimensionar um item.

Para obter informações sobre o modelo de eventos, consulte Eventos e representantes.

O exemplo de código a seguir demonstra como usar o Graphics propriedade executar personalizado desenho dos itens em um ListBox.

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


      protectedoverridevoid 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>privatevoid 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]
      staticvoid Main() 
      {
         Application.Run(new Form1());
      }

      privatevoid 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;

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

         // Create the brush using the ForeColor specified by the DrawItemEventArgsif ( foreColorBrush == null )
            foreColorBrush = new SolidBrush(e.ForeColor);
         elseif ( 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>publicclass ListBoxFontItem 
      {
         public Font Font;

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

         publicoverride 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
Quaisquer membros static (Shared no Visual Basic) públicos deste tipo são thread-safe. Não há garantia de que qualquer membro de instância seja thread-safe.

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

o.NET Framework e.NET Compact Framework não oferecem suporte a todas as versões de cada plataforma. Para obter uma lista de versões suportadas, consulte Requisitos de sistema do .NET framework.

.NET Framework

Compatível com: 3.5, 3.0, 2.0, 1.1, 1.0
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