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DrawListViewItemEventArgs (Clase)

Proporciona datos para el evento ListView.DrawItem.

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

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

El evento ListView.DrawItem le permite personalizar la apariencia de un control ListView mediante el dibujo del propietario.

Un control ListView provoca el evento ListView.DrawItem cuando la propiedad ListView.OwnerDraw se establece en true. El DrawListViewItemEventArgs pasado al controlador de eventos contiene información acerca del ListViewItem que se va a dibujar y también proporciona métodos que le ayudarán a dibujar el elemento.

Utilice la propiedad State o Item para recuperar información sobre el elemento que se va a dibujar. Utilice la propiedad DrawListViewItemEventArgs.ItemIndex para recuperar el índice del elemento.

Utilice la propiedad Graphics para hacer el dibujo real dentro del área especificada por la propiedad Bounds. Para dibujar elementos ListView estándar que no necesitan personalización, utilice los métodos DrawBackground, DrawTexty DrawFocusRectangle.

NotaNota:

Para evitar el parpadeo de los gráficos en los dibujos de propietario, reemplace el control ListView y establezca el valor de la propiedad DoubleBuffered en true. Esta característica sólo está disponible en Windows XP y la familia de Windows Server 2003 cuando la aplicación llama al método Application.EnableVisualStyles.

En el ejemplo de código siguiente se muestra cómo se proporciona un dibujo personalizado para un control ListView. El control ListView del ejemplo tiene un fondo degradado. Los subelementos con valores negativos tienen un primer plano rojo y un fondo negro.

Un controlador del evento ListView.DrawItem dibuja el fondo de elementos completos. Un controlador del evento ListView.DrawSubItem dibuja los valores de texto así como el texto y el fondo de los subelementos con valores negativos. Un controlador del evento DrawColumnHeader dibuja cada encabezado de columna.

Un componente ContextMenu proporciona una manera de cambiar entre la vista de detalles y la vista de lista. En la vista de lista, sólo se desencadena el evento ListView.DrawItem. En este caso, tanto el texto como el fondo se dibujan en el controlador del evento ListView.DrawItem.

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Globalization;
using System.Windows.Forms;

public class ListViewOwnerDraw : Form
{
    private ListView listView1 = new ListView();
    private ContextMenu contextMenu1 = new ContextMenu();

    public ListViewOwnerDraw()
    {
        // Initialize the ListView control.
        listView1.BackColor = Color.Black;
        listView1.ForeColor = Color.White;
        listView1.Dock = DockStyle.Fill;
        listView1.View = View.Details;
        listView1.FullRowSelect = true;

        // Add columns to the ListView control.
        listView1.Columns.Add("Name", 72, HorizontalAlignment.Center);
        listView1.Columns.Add("First", 72, HorizontalAlignment.Center);
        listView1.Columns.Add("Second", 72, HorizontalAlignment.Center);
        listView1.Columns.Add("Third", 72, HorizontalAlignment.Center);

        // Create items and add them to the ListView control.
        ListViewItem listViewItem1 = new ListViewItem(new string[] { "One", "20", "30", "-40" }, -1);
        ListViewItem listViewItem2 = new ListViewItem(new string[] { "Two", "-250", "145", "37" }, -1);
        ListViewItem listViewItem3 = new ListViewItem(new string[] { "Three", "200", "800", "-1,001" }, -1);
        ListViewItem listViewItem4 = new ListViewItem(new string[] { "Four", "not available", "-2", "100" }, -1);
        listView1.Items.AddRange(new ListViewItem[] { listViewItem1, listViewItem2, listViewItem3, listViewItem4 });

        // Initialize the shortcut menu and 
        // assign it to the ListView control.
        contextMenu1.MenuItems.Add("List",
            new EventHandler(menuItemList_Click));
        contextMenu1.MenuItems.Add("Details",
            new EventHandler(menuItemDetails_Click));
        listView1.ContextMenu = contextMenu1;

        // Configure the ListView control for owner-draw and add 
        // handlers for the owner-draw events.
        listView1.OwnerDraw = true;
        listView1.DrawItem += new
            DrawListViewItemEventHandler(listView1_DrawItem);
        listView1.DrawSubItem += new
            DrawListViewSubItemEventHandler(listView1_DrawSubItem);
        listView1.DrawColumnHeader += new
            DrawListViewColumnHeaderEventHandler(listView1_DrawColumnHeader);

        // Add a handler for the MouseMove event to compensate for an 
        // extra DrawItem event that occurs the first time the mouse 
        // moves over each row. 
        listView1.MouseMove += new MouseEventHandler(listView1_MouseMove);

        // Add a handler for the MouseUp event so an item can be 
        // selected by clicking anywhere along its width.
        listView1.MouseUp += new MouseEventHandler(listView1_MouseUp);

        // Initialize the form and add the ListView control to it.
        this.ClientSize = new Size(292, 79);
        this.FormBorderStyle = FormBorderStyle.FixedSingle;
        this.MaximizeBox = false;
        this.Text = "ListView OwnerDraw Example";
        this.Controls.Add(listView1);
    }

    // Clean up any resources being used.        
    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            contextMenu1.Dispose();
        }
        base.Dispose(disposing);
    }

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

    // Sets the ListView control to the List view.
    private void menuItemList_Click(object sender, EventArgs e)
    {
        listView1.View = View.List;
        listView1.Invalidate();
    }

    // Sets the ListView control to the Details view.
    private void menuItemDetails_Click(object sender, EventArgs e)
    {
        listView1.View = View.Details;

        // Reset the tag on each item to re-enable the workaround in
        // the MouseMove event handler.
        foreach (ListViewItem item in listView1.Items)
        {
            item.Tag = null;
        }
    }

    // Selects and focuses an item when it is clicked anywhere along 
    // its width. The click must normally be on the parent item text.
    private void listView1_MouseUp(object sender, MouseEventArgs e)
    {
        ListViewItem clickedItem = listView1.GetItemAt(5, e.Y);
        if (clickedItem != null)
        {
            clickedItem.Selected = true;
            clickedItem.Focused = true;
        }
    }

    // Draws the backgrounds for entire ListView items.
    private void listView1_DrawItem(object sender,
        DrawListViewItemEventArgs e)
    {
        if ((e.State & ListViewItemStates.Selected) != 0)
        {
            // Draw the background and focus rectangle for a selected item.
            e.Graphics.FillRectangle(Brushes.Maroon, e.Bounds);
            e.DrawFocusRectangle();
        }
        else
        {
            // Draw the background for an unselected item.
            using (LinearGradientBrush brush =
                new LinearGradientBrush(e.Bounds, Color.Orange,
                Color.Maroon, LinearGradientMode.Horizontal))
            {
                e.Graphics.FillRectangle(brush, e.Bounds);
            }
        }

        // Draw the item text for views other than the Details view.
        if (listView1.View != View.Details)
        {
            e.DrawText();
        }
    }

    // Draws subitem text and applies content-based formatting.
    private void listView1_DrawSubItem(object sender,
        DrawListViewSubItemEventArgs e)
    {
        TextFormatFlags flags = TextFormatFlags.Left;

        using (StringFormat sf = new StringFormat())
        {
            // Store the column text alignment, letting it default
            // to Left if it has not been set to Center or Right.
            switch (e.Header.TextAlign)
            {
                case HorizontalAlignment.Center:
                    sf.Alignment = StringAlignment.Center;
                    flags = TextFormatFlags.HorizontalCenter;
                    break;
                case HorizontalAlignment.Right:
                    sf.Alignment = StringAlignment.Far;
                    flags = TextFormatFlags.Right;
                    break;
            }

            // Draw the text and background for a subitem with a 
            // negative value. 
            double subItemValue;
            if (e.ColumnIndex > 0 && Double.TryParse(
                e.SubItem.Text, NumberStyles.Currency,
                NumberFormatInfo.CurrentInfo, out subItemValue) &&
                subItemValue < 0)
            {
                // Unless the item is selected, draw the standard 
                // background to make it stand out from the gradient.
                if ((e.ItemState & ListViewItemStates.Selected) == 0)
                {
                    e.DrawBackground();
                }

                // Draw the subitem text in red to highlight it. 
                e.Graphics.DrawString(e.SubItem.Text,
                    listView1.Font, Brushes.Red, e.Bounds, sf);

                return;
            }

            // Draw normal text for a subitem with a nonnegative 
            // or nonnumerical value.
            e.DrawText(flags);
        }
    }

    // Draws column headers.
    private void listView1_DrawColumnHeader(object sender,
        DrawListViewColumnHeaderEventArgs e)
    {
        using (StringFormat sf = new StringFormat())
        {
            // Store the column text alignment, letting it default
            // to Left if it has not been set to Center or Right.
            switch (e.Header.TextAlign)
            {
                case HorizontalAlignment.Center:
                    sf.Alignment = StringAlignment.Center;
                    break;
                case HorizontalAlignment.Right:
                    sf.Alignment = StringAlignment.Far;
                    break;
            }

            // Draw the standard header background.
            e.DrawBackground();

            // Draw the header text.
            using (Font headerFont =
                        new Font("Helvetica", 10, FontStyle.Bold))
            {
                e.Graphics.DrawString(e.Header.Text, headerFont,
                    Brushes.Black, e.Bounds, sf);
            }
        }
        return;
    }

    // Forces each row to repaint itself the first time the mouse moves over 
    // it, compensating for an extra DrawItem event sent by the wrapped 
    // Win32 control.
    private void listView1_MouseMove(object sender, MouseEventArgs e)
    {
        ListViewItem item = listView1.GetItemAt(e.X, e.Y);
        if (item != null && item.Tag == null)
        {
            listView1.Invalidate(item.Bounds);
            item.Tag = "tagged";
        }
    }

}

import System.*;
import System.Drawing.*;
import System.Drawing.Drawing2D.*;
import System.Globalization.*;
import System.Windows.Forms.*;

public class ListViewOwnerDraw extends Form
{
    private ListView myListView;
    private ContextMenu myContextMenu;

    public ListViewOwnerDraw()
    {
        // Create and initialize the ListView control.
        myListView = new ListView();
        myListView.set_BackColor(Color.get_Black());
        myListView.set_ForeColor(Color.get_White());
        myListView.set_Dock(DockStyle.Fill);
        myListView.set_View(View.Details);

        // Add columns to the ListView control.
        myListView.get_Columns().Add("Name", 72, HorizontalAlignment.Center);
        myListView.get_Columns().Add("First", 72, HorizontalAlignment.Center);
        myListView.get_Columns().Add("Second", 72, HorizontalAlignment.Center);
        myListView.get_Columns().Add("Third", 72, HorizontalAlignment.Center);

        // Create items and add them to the ListView control.
        ListViewItem listViewItem1 = new ListViewItem(new String[] 
            { "One", "20", "30", "-40" }, -1);
        ListViewItem listViewItem2 = new ListViewItem(new String[] 
            { "Two", "-250", "145", "37" }, -1);
        ListViewItem listViewItem3 = new ListViewItem(new String[] 
            { "Three", "200", "800", "-1,001" }, -1);
        ListViewItem listViewItem4 = new ListViewItem(new String[] 
            { "Four", "not available", "-2", "100" }, -1);
        myListView.get_Items().AddRange(new ListViewItem[] { listViewItem1, 
            listViewItem2, listViewItem3, listViewItem4 });

        // Create a shortcut menu for changing views and 
        // assign it to the ListView control.
        myContextMenu = new ContextMenu();
        myContextMenu.get_MenuItems().Add("List", 
            new EventHandler(menuItemList_Click));
        myContextMenu.get_MenuItems().Add("Details", 
            new EventHandler(menuItemDetails_Click));
        myListView.set_ContextMenu(myContextMenu);

        // Configure the ListView control for owner-draw and add 
        // handlers for the owner-draw events.
        myListView.set_OwnerDraw(true);
        myListView.add_DrawItem(new DrawListViewItemEventHandler(
            myListView_DrawItem));
        myListView.add_DrawSubItem(new DrawListViewSubItemEventHandler(
            myListView_DrawSubItem));

        // Add a handler for the MouseUp event so an item can be 
        // selected by clicking anywhere along its width.
        myListView.add_MouseUp(new MouseEventHandler(myListView_MouseUp));

        // Initialize the form and add the ListView control to it.
        this.set_ClientSize(new Size(292, 79));
        this.set_FormBorderStyle(get_FormBorderStyle().FixedSingle);
        this.set_MaximizeBox(false);
        this.set_Text("ListView OwnerDraw Example");
        this.get_Controls().Add(myListView);
    } //ListViewOwnerDraw

    // Clean up any resources being used.        
    protected void Dispose(boolean disposing)
    {
        if (disposing) {
            myContextMenu.Dispose();
        }
        super.Dispose(disposing);
    } //Dispose

    /** @attribute STAThread()
     */
    public static void main(String[] args)
    {
        Application.Run(new ListViewOwnerDraw());
    } //main

    // Sets the ListView control to the List view.
    private void menuItemList_Click(Object sender, EventArgs e)
    {
        myListView.set_View(View.List);
    } //menuItemList_Click

    // Sets the ListView control to the Details view.
    private void menuItemDetails_Click(Object sender, EventArgs e)
    {
        myListView.set_View(View.Details);
    } //menuItemDetails_Click

    // Selects and focuses an item when it is clicked anywhere along 
    // its width. The click must normally be on the parent item text.
    private void myListView_MouseUp(Object sender, MouseEventArgs e)
    {
        ListViewItem clickedItem = myListView.GetItemAt(5, e.get_Y());
        if (clickedItem != null) {
            clickedItem.set_Selected(true);
            clickedItem.set_Focused(true);
        }
    } //myListView_MouseUp

    // Draws the backgrounds for the column header row and for entire
    // ListView items.
    private void myListView_DrawItem(Object sender, DrawListViewItemEventArgs e)
    {
        // Draw the background for the column header row.
        if (e.get_ItemIndex() == -1) {
            e.get_Item().set_BackColor(Color.get_Black());
            e.DrawBackground();
        }
        // Draw the background for a selected item.
        else {
            if (Convert.ToInt32((e.get_State() & ListViewItemStates.Selected))
                != 0) {
                e.get_Graphics().FillRectangle(Brushes.get_Maroon(),
                    e.get_Bounds());
                e.DrawFocusRectangle();
            }
            // Draw the background for an unselected item.
            else {
                LinearGradientBrush myBrush = new LinearGradientBrush(
                    e.get_Bounds(), Color.get_Orange(), Color.get_Maroon(),
                    LinearGradientMode.Horizontal);
                try {
                    e.get_Graphics().FillRectangle(myBrush, e.get_Bounds());
                }
                finally {
                    myBrush.Dispose();
                }    
            }
        }
        // Draw the item text for views other than the Details view.
        if (!(((ListView)sender).get_View().Equals(View.Details))) {
            e.DrawText();
        }
    } //myListView_DrawItem

    // Draws subitem text and applies content-based formatting.
    private void myListView_DrawSubItem(Object sender,
        DrawListViewSubItemEventArgs e)
    {
        TextFormatFlags flags = TextFormatFlags.Left;
        StringFormat sf = new StringFormat();
        try {
            // Store the column text alignment, letting it default
            // to Left if it has not been set to Center or Right.
            if (e.get_Header().get_TextAlign().
                Equals(HorizontalAlignment.Center)) {

                sf.set_Alignment(StringAlignment.Center);
                flags = TextFormatFlags.HorizontalCenter;
            }
            else {
                if (e.get_Header().get_TextAlign().
                    Equals(HorizontalAlignment.Right)) {

                    sf.set_Alignment(StringAlignment.Far);
                    flags = TextFormatFlags.Right;
                }
            }
            // Draw the text for a column header.
            if (e.get_ItemIndex() == -1) {
                Font myFont = new Font("Helvetica", 12, FontStyle.Bold);
                try {
                    e.get_Graphics().DrawString(e.get_Item().get_Text(), 
                        myFont, Brushes.get_White(), 
                        new PointF((float)e.get_Bounds().get_X(), 
                        (float)e.get_Bounds().get_Y()), sf);
                }
                finally {
                    myFont.Dispose();
                }
                return;
            }

            // Draw the text and background for a subitem with a 
            // negative value. 
            double subItemValue = 0;
            if (e.get_ColumnIndex() > 0 && System.Double.TryParse(
                e.get_Item().get_SubItems().get_Item(e.get_ColumnIndex()).
                get_Text(), NumberStyles.Currency, 
                NumberFormatInfo.get_CurrentInfo(), subItemValue) 
                && subItemValue < 0) {

                // Unless the item is selected, draw the standard 
                // background to make it stand out from the gradient.
                if (Convert.ToInt32(e.get_ItemState() 
                    & ListViewItemStates.Selected) == 0) {
                    e.DrawBackground();
                }
                // Draw the subitem text in red to highlight it. 
                e.get_Graphics().DrawString(e.get_Item().get_SubItems().
                    get_Item(e.get_ColumnIndex()).get_Text(), 
                    ((ListView)sender).get_Font(), Brushes.get_Red(), 
                    RectangleF.op_Implicit(e.get_Bounds()), sf);

                return;
            }
            // Draw normal text for a subitem with a nonnegative 
            // or nonnumerical value.
            e.DrawText(flags);
        }
        finally {
            sf.Dispose();
        }
    } //myListView_DrawSubItem
} //ListViewOwnerDraw 

System.Object
   System.EventArgs
    System.Windows.Forms.DrawListViewItemEventArgs

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
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