Switch.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / CompMod / System / Diagnostics / Switch.cs / 1 / Switch.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 

namespace System.Diagnostics { 
    using System;
    using System.Security;
    using System.Security.Permissions;
    using System.Threading; 
    using System.Runtime.InteropServices;
    using Microsoft.Win32; 
    using System.Collections; 
    using System.Collections.Generic;
    using System.Collections.Specialized; 
    using System.Globalization;
    using System.Configuration;
    using System.Xml.Serialization;
 
    /// 
    /// Provides an base class to 
    ///    create new debugging and tracing switches. 
    /// 
    public abstract class Switch { 
        private SwitchElementsCollection switchSettings;
        private string description;
        private string displayName;
        private int    switchSetting = 0; 
        private bool   initialized = false;
        private bool   initializing = false; 
        private string switchValueString = String.Empty; 
        private StringDictionary attributes;
        private string defaultValue; 

        private static List switches = new List();

        ///  
        /// Initializes a new instance of the 
        /// class. 
        ///  
        protected Switch(string displayName, string description) : this(displayName, description, "0") {
        } 

        protected Switch(string displayName, string description, string defaultSwitchValue) {
            // displayName is used as a hashtable key, so it can never
            // be null. 
            if (displayName == null) displayName = string.Empty;
 
            this.displayName = displayName; 
            this.description = description;
 
            lock (switches) {
                switches.Add(new WeakReference(this));
            }
 
            defaultValue = defaultSwitchValue;
        } 
 
        [XmlIgnore]
        public StringDictionary Attributes { 
            get {
                Initialize();
                if (attributes == null)
                    attributes = new StringDictionary(); 
                return attributes;
            } 
        } 

        ///  
        ///    Gets a name used to identify the switch.
        /// 
        public string DisplayName {
            get { 
                return displayName;
            } 
        } 

        ///  
        ///    Gets a description of the switch.
        /// 
        public string Description {
            get { 
                return (description == null) ? string.Empty : description;
            } 
        } 

        ///  
        ///    
        ///     Indicates the current setting for this switch.
        ///    
        ///  
        protected int SwitchSetting {
            get { 
                if (!initialized) { 
                    if (!InitializeWithStatus())
                        return 0; 
                    OnSwitchSettingChanged();
                }
                return switchSetting;
            } 
            set {
                initialized = true; 
                if (switchSetting != value) { 
                    switchSetting = value;
                    OnSwitchSettingChanged(); 
                }
            }
        }
 
        protected string Value {
            get { 
                Initialize(); 
                return switchValueString;
            } 
            set {
                Initialize();
                switchValueString = value;
                try { 
                    OnValueChanged();
                } 
                catch (ArgumentException e) { 
                    throw new ConfigurationErrorsException(SR.GetString(SR.BadConfigSwitchValue, DisplayName), e);
                } 
                catch (FormatException e) {
                    throw new ConfigurationErrorsException(SR.GetString(SR.BadConfigSwitchValue, DisplayName), e);
                }
                catch (OverflowException e) { 
                    throw new ConfigurationErrorsException(SR.GetString(SR.BadConfigSwitchValue, DisplayName), e);
                } 
            } 
        }
 
        private void Initialize() {
            InitializeWithStatus();
        }
 
        private bool InitializeWithStatus() {
            if (!initialized) { 
 
                if (initializing)
                    return false; 

                initializing = true;

                if (switchSettings == null) { 
                    if (!InitializeConfigSettings())
                        return false; 
                } 

                if (switchSettings != null) { 
                    SwitchElement mySettings = switchSettings[displayName];
                    if (mySettings != null) {
                        string value = mySettings.Value;
                        if (value != null) { 
                            this.Value = value;
                        } 
                        else 
                            this.Value = defaultValue;
 
                        try {
                            TraceUtils.VerifyAttributes(mySettings.Attributes, GetSupportedAttributes(), this);
                        }
                        catch (ConfigurationException) { 
                            // if VerifyAttributes throws, clean up a little bit so we're not in a bad state.
                            initialized = false; 
                            initializing = false; 
                            throw;
                        } 

                        attributes = new StringDictionary();
                        attributes.contents = mySettings.Attributes;
                    } 
                    else {
                        // We don't use the property here because we don't want to catch exceptions 
                        // and rethrow them as ConfigurationException.  In this case there's no config. 
                        switchValueString = defaultValue;
                        OnValueChanged(); 
                    }
                }
                else {
                    // We don't use the property here because we don't want to catch exceptions 
                    // and rethrow them as ConfigurationException.  In this case there's no config.
                    switchValueString = defaultValue; 
                    OnValueChanged(); 
                }
 
                initialized = true;
                initializing = false;
            }
 
            return true;
        } 
 
        private bool InitializeConfigSettings() {
            if (switchSettings != null) 
                return true;

            if (!DiagnosticsConfiguration.CanInitialize())
                return false; 

            // This hashtable is case-insensitive. 
            switchSettings = DiagnosticsConfiguration.SwitchSettings; 
            return true;
        } 

        virtual protected internal string[] GetSupportedAttributes() {
            return null;
        } 

        ///  
        ///     This method is invoked when a switch setting has been changed.  It will 
        ///     be invoked the first time a switch reads its value from the registry
        ///     or environment, and then it will be invoked each time the switch's 
        ///     value is changed.
        /// 
        protected virtual void OnSwitchSettingChanged() {
        } 

        protected virtual void OnValueChanged() { 
            SwitchSetting = Int32.Parse(Value, CultureInfo.InvariantCulture); 
        }
 
        internal static void RefreshAll() {

            lock (switches) {
                for (int i=0; i

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