Questa documentazione è stata archiviata e non viene gestita.

Classe ToolStripItem

Nota: questa classe è stata introdotta con .NET Framework versione 2.0.

Rappresenta la classe base che gestisce gli eventi e il layout di tutti gli elementi che possono essere presenti in un controllo ToolStrip o ToolStripDropDown.

Spazio dei nomi: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public abstract class ToolStripItem : Component, IDropTarget, IComponent, IDisposable
public abstract class ToolStripItem extends Component implements IDropTarget, IComponent, 
	IDisposable
public abstract class ToolStripItem extends Component implements IDropTarget, IComponent, 
	IDisposable

ToolStripItem è un elemento, ad esempio un pulsante, una casella combinata, una casella di testo o un'etichetta, che può essere contenuto in un controllo ToolStrip o ToolStripDropDown. Questo oggetto è simile a un menu di scelta rapida di Windows. La classe ToolStrip gestisce le operazioni di disegno e l'input della tastiera e del mouse, compreso l'input mediante trascinamento della selezione, per tali elementi, mentre la classe ToolStripItem gestisce gli eventi e il layout.

Nella tabella riportata di seguito sono visualizzati gli elementi che derivano dalla classe ToolStripItem e che, pertanto, possono essere contenuti in un oggetto ToolStrip o ToolStripDropDown.

Elemento

Descrizione

ToolStripButton

Pulsante della barra degli strumenti che supporta immagini e testo.

ToolStripLabel

Etichetta di testo in genere utilizzata in una barra di stato o in un controllo ToolStrip come commento o titolo.

ToolStripSeparator

Area non selezionabile oppure area con una barra verticale in cui sono raggruppati visivamente gli elementi.

ToolStripControlHost

Oggetto ToolStripItem che contiene un ToolStripComboBox, ToolStripTextBox, ToolStripProgressBar, altri controlli Windows Form o controlli personalizzati.

Un elemento ToolStripComboBox è costituito da una casella di testo in cui l'utente può immettere del testo e da un elenco che può essere utilizzato dall'utente per selezionare il testo da inserire nella casella di testo.

Un elemento ToolStripTextBox consente all'utente di immettere del testo.

Oggetto ToolStripProgressBar che rappresenta un controllo indicatore di stato di Windows contenuto in un oggetto StatusStrip.

ToolStripDropDownItem

Oggetto ToolStripItem che contiene un elemento ToolStripMenuItem, un elemento ToolStripSplitButton e un elemento ToolStripDropDownButton.

Un elemento ToolStripMenuItem è un'opzione selezionabile visualizzata in un menu o in un menu di scelta rapida.

Un elemento ToolStripSplitButton è costituito dalla combinazione di un normale pulsante e un pulsante a discesa.

Un elemento ToolStripDropDownButton è un pulsante che supporta la funzionalità a discesa.

ToolStripStatusLabel

Pannello in un controllo StatusStrip.

Nell'esempio di codice riportato di seguito viene illustrato come implementare un controllo ToolStripItem personalizzato.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace RolloverItemDemoLib
{
    // This class implements a ToolStripItem that highlights
    // its border and text when the mouse enters enters its
    // client rectangle. It has a clickable state which is
    // exposed through the Clicked property and displayed
    // by highlighting or graying out the item's image. 
    public class RolloverItem : ToolStripItem
    {
        private bool clickedValue = false;
        private bool rolloverValue = false;

        private Rectangle imageRect;
        private Rectangle textRect;

        // For brevity, this implementation limits the possible 
        // TextDirection values to ToolStripTextDirection.Horizontal. 
        public override ToolStripTextDirection TextDirection
        {
            get
            {
                return base.TextDirection;
            }
            set
            {
                if (value == ToolStripTextDirection.Horizontal)
                {
                    base.TextDirection = value;
                }
                else
                {
                    throw new ArgumentException(
                        "RolloverItem supports only horizontal text.");
                }
            }
        }

        // For brevity, this implementation limits the possible 
        // TextImageRelation values to ImageBeforeText and TextBeforeImage. 
        public new TextImageRelation TextImageRelation
        {
            get
            {
                return base.TextImageRelation;
            }

            set
            {
                if (value == TextImageRelation.ImageBeforeText || 
                    value == TextImageRelation.TextBeforeImage)
                {
                    base.TextImageRelation = value;
                }
                else
                {
                    throw new ArgumentException(
                        "Unsupported TextImageRelation value.");
                }
            }
        }
        
        // This property returns true if the mouse is 
        // inside the client rectangle.
        public bool Rollover
        {
            get
            {
                return this.rolloverValue;
            }   
        }

        // This property returns true if the item 
        // has been toggled into the clicked state.
        // Clicking again toggles it to the 
        // unclicked state.
        public bool Clicked
        {
            get
            {
                return this.clickedValue;
            }
        }

        // The method defines the behavior of the Click event.
        // It simply toggles the state of the clickedValue field.
        protected override void OnClick(EventArgs e)
        {
            base.OnClick(e);

            this.clickedValue ^= true;
        }

        // The method defines the behavior of the DoubleClick 
        // event. It shows a MessageBox with the item's text.
        protected override void OnDoubleClick(EventArgs e)
        {
            base.OnDoubleClick(e);

            string msg = String.Format("Item: {0}", this.Text);

            MessageBox.Show(msg);
        }

        // This method defines the behavior of the MouseEnter event.
        // It sets the state of the rolloverValue field to true and
        // tells the control to repaint.
        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);

            this.rolloverValue = true;

            this.Invalidate();
        }

        // This method defines the behavior of the MouseLeave event.
        // It sets the state of the rolloverValue field to false and
        // tells the control to repaint.
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);

            this.rolloverValue = false;

            this.Invalidate();
        }

        // This method defines the painting behavior of the control.
        // It performs the following operations:
        //
        // Computes the layout of the item's image and text.
        // Draws the item's background image.
        // Draws the item's image.
        // Draws the item's text.
        //
        // Drawing operations are implemented in the 
        // RolloverItemRenderer class.
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            if (this.Owner != null)
            {
                // Find the dimensions of the image and the text 
                // areas of the item. 
                this.ComputeImageAndTextLayout();

                // Draw the background. This includes drawing a highlighted 
                // border when the mouse is in the client area.
                ToolStripItemRenderEventArgs ea = new ToolStripItemRenderEventArgs(
                     e.Graphics,
                     this);
                this.Owner.Renderer.DrawItemBackground(ea);

                // Draw the item's image. 
                ToolStripItemImageRenderEventArgs irea =
                    new ToolStripItemImageRenderEventArgs(
                    e.Graphics,
                    this,
                    imageRect );
                this.Owner.Renderer.DrawItemImage(irea);

                // If the item is on a drop-down, give its
                // text a different highlighted color.
                Color highlightColor = 
                    this.IsOnDropDown ?
                    Color.Salmon : SystemColors.ControlLightLight;

                // Draw the text, and highlight it if the 
                // the rollover state is true.
                ToolStripItemTextRenderEventArgs rea =
                    new ToolStripItemTextRenderEventArgs(
                    e.Graphics,
                    this,
                    base.Text,
                    textRect,
                    this.rolloverValue ? highlightColor : base.ForeColor,
                    base.Font,
                    base.TextAlign);
                this.Owner.Renderer.DrawItemText(rea);
            }
        }

        // This utility method computes the layout of the 
        // RolloverItem control's image area and the text area.
        // For brevity, only the following settings are 
        // supported:
        //
        // ToolStripTextDirection.Horizontal
        // TextImageRelation.ImageBeforeText 
        // TextImageRelation.ImageBeforeText
        // 
        // It would not be difficult to support vertical text
        // directions and other image/text relationships.
        private void ComputeImageAndTextLayout()
        {
            Rectangle cr = base.ContentRectangle;
            Image img = base.Owner.ImageList.Images[base.ImageKey];

            // Compute the center of the item's ContentRectangle.
            int centerY = (cr.Height - img.Height) / 2;

            // Find the dimensions of the image and the text 
            // areas of the item. The text occupies the space 
            // not filled by the image. 
            if (base.TextImageRelation == TextImageRelation.ImageBeforeText &&
                base.TextDirection == ToolStripTextDirection.Horizontal)
            {
                imageRect = new Rectangle(
                    base.ContentRectangle.Left,
                    centerY,
                    base.Image.Width,
                    base.Image.Height);

                textRect = new Rectangle(
                    imageRect.Width,
                    base.ContentRectangle.Top,
                    base.ContentRectangle.Width - imageRect.Width,
                    base.ContentRectangle.Height);
            }
            else if (base.TextImageRelation == TextImageRelation.TextBeforeImage &&
                     base.TextDirection == ToolStripTextDirection.Horizontal)
            {
                imageRect = new Rectangle(
                    base.ContentRectangle.Right - base.Image.Width,
                    centerY,
                    base.Image.Width,
                    base.Image.Height);

                textRect = new Rectangle(
                    base.ContentRectangle.Left,
                    base.ContentRectangle.Top,
                    imageRect.X,
                    base.ContentRectangle.Bottom);
            }
        }
    }

    #region RolloverItemRenderer

    // This is the custom renderer for the RolloverItem control.
    // It draws a border around the item when the mouse is
    // in the item's client area. It also draws the item's image
    // in an inactive state (grayed out) until the user clicks
    // the item to toggle its "clicked" state.
    internal class RolloverItemRenderer : ToolStripSystemRenderer
    {
        protected override void OnRenderItemImage(
            ToolStripItemImageRenderEventArgs e)
        {
            base.OnRenderItemImage(e);

            RolloverItem item = e.Item as RolloverItem;

            // If the ToolSTripItem is of type RolloverItem, 
            // perform custom rendering for the image.
            if (item != null)
            {
                if (item.Clicked)
                {
                    // The item is in the clicked state, so 
                    // draw the image as usual.
                    e.Graphics.DrawImage(
                        e.Image,
                        e.ImageRectangle.X,
                        e.ImageRectangle.Y);
                }
                else
                {
                    // In the unclicked state, gray out the image.
                    ControlPaint.DrawImageDisabled(
                        e.Graphics,
                        e.Image,
                        e.ImageRectangle.X,
                        e.ImageRectangle.Y,
                        item.BackColor);
                }
            }
        }

        // This method defines the behavior for rendering the
        // background of a ToolStripItem. If the item is a
        // RolloverItem, it paints the item's BackgroundImage 
        // centered in the client area. If the mouse is in the 
        // item's client area, a border is drawn around it.
        // If the item is on a drop-down or if it is on the
        // overflow, a gradient is painted in the background.
        protected override void OnRenderItemBackground(
            ToolStripItemRenderEventArgs e)
        {
            base.OnRenderItemBackground(e);

            RolloverItem item = e.Item as RolloverItem;

            // If the ToolSTripItem is of type RolloverItem, 
            // perform custom rendering for the background.
            if (item != null)
            {
                if (item.Placement == ToolStripItemPlacement.Overflow ||
                    item.IsOnDropDown)
                {
                    using (LinearGradientBrush b = new LinearGradientBrush(
                        item.ContentRectangle,
                        Color.Salmon,
                        Color.DarkRed,
                        0f,
                        false))
                    {
                        e.Graphics.FillRectangle(b, item.ContentRectangle);
                    }
                }

                // The RolloverItem control only supports 
                // the ImageLayout.Center setting for the
                // BackgroundImage property.
                if (item.BackgroundImageLayout == ImageLayout.Center)
                {
                    // Get references to the item's ContentRectangle
                    // and BackgroundImage, for convenience.
                    Rectangle cr = item.ContentRectangle;
                    Image bgi = item.BackgroundImage;

                    // Compute the center of the item's ContentRectangle.
                    int centerX = (cr.Width - bgi.Width) / 2;
                    int centerY = (cr.Height - bgi.Height) / 2;

                    // If the item is selected, draw the background
                    // image as usual. Otherwise, draw it as disabled.
                    if (item.Selected)
                    {
                        e.Graphics.DrawImage(bgi, centerX, centerY);
                    }
                    else
                    {
                        ControlPaint.DrawImageDisabled(
                                e.Graphics,
                                bgi,
                                centerX,
                                centerY,
                                item.BackColor);
                    }
                }

                // If the item is in the rollover state, 
                // draw a border around it.
                if (item.Rollover)
                {
                    ControlPaint.DrawFocusRectangle(
                        e.Graphics,
                        item.ContentRectangle);
                }
            }
        }

    #endregion

    }

    // This form tests various features of the RolloverItem
    // control. RolloverItem conrols are created and added
    // to the form's ToolStrip. They are also created and 
    // added to a button's ContextMenuStrip. The behavior
    // of the RolloverItem control differs depending on 
    // the type of parent control.
    public class RolloverItemTestForm : Form
    {
        private System.Windows.Forms.ToolStrip toolStrip1;
        private System.Windows.Forms.Button button1;

        private string infoIconKey = "Information icon";
        private string handIconKey = "Hand icon";
        private string exclIconKey = "Exclamation icon";
        private string questionIconKey = "Question icon";
        private string warningIconKey = "Warning icon ";

        private System.ComponentModel.IContainer components = null;

        public RolloverItemTestForm()
        {
            InitializeComponent();

            // Set up the form's ToolStrip control.
            InitializeToolStrip();

            // Set up the ContextMenuStrip for the button.
            InitializeContextMenu();
        }

        // This utility method initializes the ToolStrip control's 
        // image list. For convenience, icons from the SystemIcons 
        // class are used for this demonstration, but any images
        // could be used.
        private void InitializeImageList(ToolStrip ts)
        {
            if (ts.ImageList == null)
            {
                ts.ImageList = new ImageList();
                ts.ImageList.ImageSize = SystemIcons.Exclamation.Size;

                ts.ImageList.Images.Add(
                    this.infoIconKey,
                    SystemIcons.Information);

                ts.ImageList.Images.Add(
                    this.handIconKey,
                    SystemIcons.Hand);

                ts.ImageList.Images.Add(
                    this.exclIconKey,
                    SystemIcons.Exclamation);

                ts.ImageList.Images.Add(
                    this.questionIconKey,
                    SystemIcons.Question);

                ts.ImageList.Images.Add(
                    this.warningIconKey,
                    SystemIcons.Warning);
            }
        }

        private void InitializeToolStrip()
        {
            this.InitializeImageList(this.toolStrip1);

            this.toolStrip1.Renderer = new RolloverItemRenderer();

            RolloverItem item = this.CreateRolloverItem(
                this.toolStrip1,
                "RolloverItem on ToolStrip",
                this.Font,
                infoIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            this.toolStrip1.Items.Add(item);

            item = this.CreateRolloverItem(
                this.toolStrip1,
                "RolloverItem on ToolStrip",
                this.Font,
                infoIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            this.toolStrip1.Items.Add(item);
        }

        private void InitializeContextMenu()
        {
            Font f = new System.Drawing.Font(
                "Arial",
                18f,
                FontStyle.Bold);

            ContextMenuStrip cms = new ContextMenuStrip();
            this.InitializeImageList(cms);

            cms.Renderer = new RolloverItemRenderer();
            cms.AutoSize = true;
            cms.ShowCheckMargin = false;
            cms.ShowImageMargin = false;

            RolloverItem item = this.CreateRolloverItem(
                cms,
                "RolloverItem on ContextMenuStrip",
                f,
                handIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            item = this.CreateRolloverItem(
                cms,
                "Another RolloverItem on ContextMenuStrip",
                f,
                questionIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            item = this.CreateRolloverItem(
                cms,
                "And another RolloverItem on ContextMenuStrip",
                f,
                warningIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            cms.Closing += new ToolStripDropDownClosingEventHandler(cms_Closing);

            this.button1.ContextMenuStrip = cms;
        }

        // This method handles the ContextMenuStrip 
        // control's Closing event. It prevents the 
        // RolloverItem from closing the drop-down  
        // when the item is clicked.
        void cms_Closing(object sender, ToolStripDropDownClosingEventArgs e)
        {
            if (e.CloseReason == ToolStripDropDownCloseReason.ItemClicked)
            {
                e.Cancel = true;
            }
        }

        // This method handles the Click event for the button.
        // it selects the first item in the ToolStrip control
        // by using the ToolStripITem.Select method.
        private void button1_Click(object sender, EventArgs e)
        {
            RolloverItem item = this.toolStrip1.Items[0] as RolloverItem;

            if (item != null)
            {
                item.Select();

                this.Invalidate();
            }
        }

        // This utility method creates a RolloverItem 
        // and adds it to a ToolStrip control.
        private RolloverItem CreateRolloverItem(
            ToolStrip owningToolStrip,
            string txt,
            Font f,
            string imgKey,
            TextImageRelation tir,
            string backImgKey)
        {
            RolloverItem item = new RolloverItem();

            item.Alignment = ToolStripItemAlignment.Left;
            item.AllowDrop = false;
            item.AutoSize = true;

            item.BackgroundImage = owningToolStrip.ImageList.Images[backImgKey];
            item.BackgroundImageLayout = ImageLayout.Center;
            item.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText;
            item.DoubleClickEnabled = true;
            item.Enabled = true;
            item.Font = f;

            // These assignments are equivalent. Each assigns an
            // image from the owning toolstrip's image list.
            item.ImageKey = imgKey;
            //item.Image = owningToolStrip.ImageList.Images[infoIconKey];
            //item.ImageIndex = owningToolStrip.ImageList.Images.IndexOfKey(infoIconKey);
            item.ImageScaling = ToolStripItemImageScaling.None;

            item.Owner = owningToolStrip;
            item.Padding = new Padding(2);
            item.Text = txt;
            item.TextAlign = ContentAlignment.MiddleLeft;
            item.TextDirection = ToolStripTextDirection.Horizontal;
            item.TextImageRelation = tir;

            return item;
        }

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

        #region Windows Form Designer generated code

        private void InitializeComponent()
        {
            this.toolStrip1 = new System.Windows.Forms.ToolStrip();
            this.button1 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // toolStrip1
            // 
            this.toolStrip1.AllowItemReorder = true;
            this.toolStrip1.Location = new System.Drawing.Point(0, 0);
            this.toolStrip1.Name = "toolStrip1";
            this.toolStrip1.Size = new System.Drawing.Size(845, 25);
            this.toolStrip1.TabIndex = 0;
            this.toolStrip1.Text = "toolStrip1";
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 100);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(86, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "Click to select";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // RolloverItemTestForm
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 14F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.AutoSize = true;
            this.ClientSize = new System.Drawing.Size(845, 282);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.toolStrip1);
            this.Font = new System.Drawing.Font("Arial", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Name = "RolloverItemTestForm";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion
    }

    static class Program
    {   
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new RolloverItemTestForm());
        }
    }

}

I membri statici pubblici (Shared in Visual Basic) di questo tipo sono validi per le operazioni multithreading. I membri di istanza non sono garantiti come thread safe.

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

.NET Framework non supporta tutte le versioni di ciascuna piattaforma. Per un elenco delle versioni supportate, vedere Requisiti di sistema.

.NET Framework

Supportato in: 2.0
Mostra: