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Proprietà SystemInformation.HighContrast

Aggiornamento: novembre 2007

Ottiene un valore che indica se l'utente ha attivato la funzionalità di accesso facilitato in modalità Contrasto elevato.

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

public static bool HighContrast { get; }
/** @property */
public static boolean get_HighContrast()

public static function get HighContrast () : boolean

Valore proprietà

Tipo: System.Boolean

true se l'utente ha attivato la modalità Contrasto elevato; in caso contrario, false.

La funzionalità di accessibilità in modalità Contrasto elevato consente di migliorare la visibilità dello schermo per alcuni utenti attivando una combinazione di colori alternativi che enfatizza il contrasto degli elementi visualizzati. In alcune combinazioni viene modificata anche la dimensione dei caratteri per agevolare la lettura.

La modalità Contrasto elevato può essere attivata o disattivata tramite l'opzione Accesso facilitato del Pannello di controllo.

Nota:

Questa proprietà è supportata esclusivamente in Windows 98, Windows Millennium Edition, Windows 2000, Windows XP e Windows Server 2003.

Nell'esempio di codice riportato di seguito vengono elencate tutte le proprietà della classe SystemInformation in un oggetto ListBox e viene visualizzato il valore corrente della proprietà in un oggetto TextBox quando viene selezionato un elemento dell'elenco.

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Windows.Forms;

namespace SystemInfoBrowser
{
    public class SystemInfoBrowserForm : System.Windows.Forms.Form
    {
        private System.Windows.Forms.ListBox listBox1;
        private System.Windows.Forms.TextBox textBox1;        

        public SystemInfoBrowserForm()
	    {
            this.SuspendLayout();
            InitForm();

            // Add each property of the SystemInformation class to the list box.
            Type t = typeof(System.Windows.Forms.SystemInformation);            
            PropertyInfo[] pi = t.GetProperties();            
            for( int i=0; i<pi.Length; i++ )
                listBox1.Items.Add( pi[i].Name );            
            textBox1.Text = "The SystemInformation class has "+pi.Length.ToString()+" properties.\r\n";

            // Configure the list item selected handler for the list box to invoke a 
            // method that displays the value of each property.
            listBox1.SelectedIndexChanged += new EventHandler(listBox1_SelectedIndexChanged);
            this.ResumeLayout(false);
	    }
		
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Return if no list item is selected.
            if( listBox1.SelectedIndex == -1 ) return;
            // Get the property name from the list item.
            string propname = listBox1.Text;

            if( propname == "PowerStatus" )
            {
                // Cycle and display the values of each property of the PowerStatus property.
                textBox1.Text += "\r\nThe value of the PowerStatus property is:";                                
                Type t = typeof(System.Windows.Forms.PowerStatus);
                PropertyInfo[] pi = t.GetProperties();            
                for( int i=0; i<pi.Length; i++ )
                {
                    object propval = pi[i].GetValue(SystemInformation.PowerStatus, null);            
                    textBox1.Text += "\r\n    PowerStatus."+pi[i].Name+" is: "+propval.ToString();
                }
            }
            else
            {
                // Display the value of the selected property of the SystemInformation type.
                Type t = typeof(System.Windows.Forms.SystemInformation);
                PropertyInfo[] pi = t.GetProperties();            
                PropertyInfo prop = null;
                for( int i=0; i<pi.Length; i++ )
                    if( pi[i].Name == propname )
                    {
                        prop = pi[i];
                        break;           
                    }
                object propval = prop.GetValue(null, null);            
                textBox1.Text += "\r\nThe value of the "+propname+" property is: "+propval.ToString();
            }
        }

        private void InitForm()
        {
            // Initialize the form settings
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.textBox1 = new System.Windows.Forms.TextBox();            
            this.listBox1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
                | System.Windows.Forms.AnchorStyles.Left) | System.Windows.Forms.AnchorStyles.Right)));
            this.listBox1.Location = new System.Drawing.Point(8, 16);
            this.listBox1.Size = new System.Drawing.Size(172, 496);
            this.listBox1.TabIndex = 0;            
            this.textBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
                | System.Windows.Forms.AnchorStyles.Right)));
            this.textBox1.Location = new System.Drawing.Point(188, 16);
            this.textBox1.Multiline = true;
            this.textBox1.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;           
            this.textBox1.Size = new System.Drawing.Size(420, 496);
            this.textBox1.TabIndex = 1;            
            this.ClientSize = new System.Drawing.Size(616, 525);            
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.listBox1);            
            this.Text = "Select a SystemInformation property to get the value of";                   
        }

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


package SystemInfoBrowser;

import System.*;
import System.Collections.*;
import System.ComponentModel.*;
import System.Drawing.*;
import System.Reflection.*;
import System.Windows.Forms.*;

public class SystemInfoBrowserForm extends System.Windows.Forms.Form
{
    private System.Windows.Forms.ListBox listBox1;
    private System.Windows.Forms.TextBox textBox1;

    public SystemInfoBrowserForm()
    {
        this.SuspendLayout();
        InitForm();
        // Add each property of the SystemInformation class to the list box.
        Type t = System.Windows.Forms.SystemInformation.class.ToType();
        PropertyInfo pi[] = t.GetProperties();
        for (int i = 0; i < pi.length; i++) {
            listBox1.get_Items().Add(pi[i].get_Name());
        }
        textBox1.set_Text("The SystemInformation class has "
            + ((Int32)pi.length).ToString() + " properties.\r\n");
        // Configure the list item selected handler for the list box to invoke
        // a method that displays the value of each property.
        listBox1.add_SelectedIndexChanged(
            new EventHandler(listBox1_SelectedIndexChanged));
        this.ResumeLayout(false);
    } //SystemInfoBrowserForm

    private void listBox1_SelectedIndexChanged(Object sender, EventArgs e)
    {
        // Return if no list item is selected.
        if (listBox1.get_SelectedIndex() == -1) {
            return;
        }
        // Get the property name from the list item.
        String propname = listBox1.get_Text();

        if (propname.Equals("PowerStatus")) {
            // Cycle and display the values of each property of the
            // PowerStatus property.
            textBox1.set_Text(textBox1.get_Text()
                + "\r\nThe value of the PowerStatus property is:");
            Type t = System.Windows.Forms.PowerStatus.class.ToType();
            PropertyInfo pi[] = t.GetProperties();
            for (int i = 0; i < pi.length; i++) {
                Object propval = pi[i].GetValue(
                    SystemInformation.get_PowerStatus(), null);
                textBox1.set_Text(textBox1.get_Text()
                    + "\r\n    PowerStatus." + pi[i].get_Name()
                    + " is: " + propval.ToString());
            }
        }
        else {
            // Display the value of the selected property of the
            // SystemInformation type.
            Type t = System.Windows.Forms.SystemInformation.class.ToType();
            PropertyInfo pi[] = t.GetProperties();
            PropertyInfo prop = null;
            for (int i = 0; i < pi.length; i++) {
                if (pi[i].get_Name().Equals(propname)) {
                    prop = pi[i];
                    break;
                }
            }
            Object propval = prop.GetValue(null, null);
            textBox1.set_Text(textBox1.get_Text() + "\r\nThe value of the "
                + propname + " property is: " + propval.ToString());
        }
    } //listBox1_SelectedIndexChanged

    private void InitForm()
    {
        // Initialize the form settings
        this.listBox1 = new System.Windows.Forms.ListBox();
        this.textBox1 = new System.Windows.Forms.TextBox();
        this.listBox1.set_Anchor((System.Windows.Forms.AnchorStyles)
            (System.Windows.Forms.AnchorStyles.Top
            | System.Windows.Forms.AnchorStyles.Bottom
            | System.Windows.Forms.AnchorStyles.Left
            | System.Windows.Forms.AnchorStyles.Right));
        this.listBox1.set_Location(new System.Drawing.Point(8, 16));
        this.listBox1.set_Size(new System.Drawing.Size(172, 496));
        this.listBox1.set_TabIndex(0);
        this.textBox1.set_Anchor((System.Windows.Forms.AnchorStyles)
            (System.Windows.Forms.AnchorStyles.Top
            | System.Windows.Forms.AnchorStyles.Bottom
            | System.Windows.Forms.AnchorStyles.Right));
        this.textBox1.set_Location(new System.Drawing.Point(188, 16));
        this.textBox1.set_Multiline(true);
        this.textBox1.set_ScrollBars(System.Windows.Forms.ScrollBars.Vertical);
        this.textBox1.set_Size(new System.Drawing.Size(420, 496));
        this.textBox1.set_TabIndex(1);
        this.set_ClientSize(new System.Drawing.Size(616, 525));
        this.get_Controls().Add(this.textBox1);
        this.get_Controls().Add(this.listBox1);
        this.set_Text("Select a SystemInformation property to get the value of");
    } //InitForm

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


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

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

.NET Framework

Supportato in: 3.5, 3.0, 2.0, 1.1, 1.0

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