CategoryValueConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Services / Monitoring / system / Diagnosticts / Design / CategoryValueConverter.cs / 1 / CategoryValueConverter.cs
                        

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

namespace System.Diagnostics.Design { 
    using System.Runtime.Serialization.Formatters; 
    using System.Globalization;
    using System.Diagnostics; 
    using System;
    using System.Windows.Forms.ComponentModel;
    using System.ComponentModel;
    using System.ComponentModel.Design; 
    using System.Collections;
 
    internal class CategoryValueConverter : TypeConverter { 
        /// 
        ///  
        ///    
        ///       Provides a  that specifies the
        ///       possible values for the enumeration.
        ///     
        /// 
        private StandardValuesCollection values; 
        private string previousMachineName; 

        ///  
        /// 
        ///    
        ///       Initializes a new instance of the 'CategoryValueConverter' class for the given type.
        ///     
        /// 
        public CategoryValueConverter() { 
        } 

        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) { 
            if (sourceType == typeof(string)) {
                return true;
            }
            return base.CanConvertFrom(context, sourceType); 
        }
 
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) { 
            if (value is string) {
                string text = ((string)value).Trim(); 
                return text;
            }
            return base.ConvertFrom(context, culture, value);
        } 

 
        ///  
        /// 
        ///  
        ///    Gets a collection of standard values for the data type this validator is
        ///       designed for.
        /// 
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { 
            PerformanceCounter counter = (context == null) ? null : context.Instance as PerformanceCounter;
            string machineName = "."; 
            if (counter != null) { 
                machineName = counter.MachineName;
            } 

            if (machineName == previousMachineName)
                return values;
            else 
                previousMachineName = machineName;
 
            try { 
                PerformanceCounter.CloseSharedResources();
                PerformanceCounterCategory[] cats = PerformanceCounterCategory.GetCategories(machineName); 

                string[] retVal = new string[cats.Length];

                for (int i = 0; i < cats.Length; i++) { 
                    retVal[i] = cats[i].CategoryName;
                } 
 
                Array.Sort(retVal, Comparer.Default);
                values = new StandardValuesCollection(retVal); 
            }
            catch (Exception) {
                values = null;
            } 

            return values; 
        } 

        ///  
        /// 
        /// 
        ///    Gets a value indicating
        ///       whether this object 
        ///       supports a standard set of values that can be picked
        ///       from a list using the specified context. 
        ///  
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) {
            return true; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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