DisplayInformation.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / DisplayInformation.cs / 1305376 / DisplayInformation.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 
/*
 */ 
 
namespace System.Windows.Forms {
    using Microsoft.Win32; 
    using System.Security;
    using System.Security.Permissions;

    internal class DisplayInformation { 

        private static bool highContrast;               //whether we are under hight contrast mode 
        private static bool lowRes;                     //whether we are under low resolution mode 
        private static bool isTerminalServerSession;    //whether this application is run on a terminal server (remote desktop)
        private static bool highContrastSettingValid;   //indicates whether the high contrast setting is correct 
        private static bool lowResSettingValid;         //indicates whether the low resolution setting is correct
        private static bool terminalSettingValid;       //indicates whether the terminal server setting is correct
        private static short bitsPerPixel;
        private static bool dropShadowSettingValid; 
        private static bool dropShadowEnabled;
        private static bool menuAccessKeysUnderlinedValid; 
        private static bool menuAccessKeysUnderlined; 

 
        static DisplayInformation() {
            SystemEvents.UserPreferenceChanging += new UserPreferenceChangingEventHandler(UserPreferenceChanging);
            SystemEvents.DisplaySettingsChanging += new EventHandler(DisplaySettingsChanging);
        } 

        public static short BitsPerPixel { 
           get { 
               if (bitsPerPixel == 0) {
                    // we used to iterate through all screens, but 
                    // for some reason unused screens can temparily appear
                    // in the AllScreens collection - we would honor the display
                    // setting of an unused screen.
                    // According to EnumDisplayMonitors, a primary screen check should be sufficient 
                    bitsPerPixel = (short)Screen.PrimaryScreen.BitsPerPixel;
 
               } 
               return bitsPerPixel;
           } 
       }

        ///
        ///tests to see if the monitor is in low resolution mode (8-bit color depth or less). 
        ///
        public static bool LowResolution { 
            get { 

                if (lowResSettingValid && !lowRes) { 
                    return lowRes;
                }
                // dont cache if we're in low resolution.
                lowRes = BitsPerPixel <= 8; 
                lowResSettingValid = true;
                return lowRes; 
            } 
        }
 
        ///
        ///tests to see if we are under high contrast mode
        ///
        public static bool HighContrast { 
            get {
                if (highContrastSettingValid) { 
                    return highContrast; 
                }
                highContrast = SystemInformation.HighContrast; 
                highContrastSettingValid = true;
                return highContrast;
            }
        } 
        public static bool IsDropShadowEnabled {
            get { 
                if (dropShadowSettingValid) { 
                    return dropShadowEnabled;
                } 
                dropShadowEnabled = SystemInformation.IsDropShadowEnabled;
                dropShadowSettingValid = true;
                return dropShadowEnabled;
            } 
        }
 
        /// 
        ///test to see if we are under terminal server mode
        /// 
        public static bool TerminalServer {
            get {
                if (terminalSettingValid) {
                    return isTerminalServerSession; 
                }
 
                isTerminalServerSession = SystemInformation.TerminalServerSession; 
                terminalSettingValid = true;
                return isTerminalServerSession; 
            }
        }

        // return if mnemonic underlines should always be there regardless of ALT 
        public static bool MenuAccessKeysUnderlined {
            get { 
                 if (menuAccessKeysUnderlinedValid) { 
                     return menuAccessKeysUnderlined;
                 } 
                 menuAccessKeysUnderlined = SystemInformation.MenuAccessKeysUnderlined;
                 menuAccessKeysUnderlinedValid = true;
                 return menuAccessKeysUnderlined;
            } 
        }
 
        /// 
        ///event handler for change in display setting
        /// 
        private static void DisplaySettingsChanging(object obj, EventArgs ea)
        {
            highContrastSettingValid = false;
            lowResSettingValid = false; 
            terminalSettingValid = false;
            dropShadowSettingValid = false; 
            menuAccessKeysUnderlinedValid = false; 

        } 

        ///
        ///event handler for change in user preference
        /// 
        private static void UserPreferenceChanging(object obj, UserPreferenceChangingEventArgs e) {
            highContrastSettingValid = false; 
            lowResSettingValid = false; 
            terminalSettingValid = false;
            dropShadowSettingValid = false; 
            bitsPerPixel = 0;

            if (e.Category == UserPreferenceCategory.General) {
                menuAccessKeysUnderlinedValid =false; 
            }
        } 
    } 
    }

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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