DurationConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / DurationConverter.cs / 2 / DurationConverter.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//  Microsoft Windows Client Platform
//  Copyright (c) Microsoft Corporation, 2004
//
//  File: DurationConverter.cs 
//-----------------------------------------------------------------------------
 
using System; 
using System.ComponentModel;
using System.ComponentModel.Design.Serialization; 
using System.Diagnostics;
using System.Globalization;
using System.Reflection;
using System.Security; 

namespace System.Windows 
{ 
    /// 
    /// Provides a type converter to convert Duration to and from other representations. 
    /// 
    public class DurationConverter : TypeConverter
    {
        ///  
        /// CanConvertFrom - Returns whether or not this class can convert from a given type
        ///  
        ///  
        public override bool CanConvertFrom(ITypeDescriptorContext td, Type t)
        { 
            if (t == typeof(string))
            {
                return true;
            } 
            else
            { 
                return false; 
            }
        } 

        /// 
        /// TypeConverter method override.
        ///  
        /// ITypeDescriptorContext
        /// Type to convert to 
        /// true if conversion is possible 
        /// 
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) 
        {
            if (   destinationType == typeof(InstanceDescriptor)
                || destinationType == typeof(string))
            { 
                return true;
            } 
            else 
            {
                return false; 
            }
        }

        ///  
        /// ConvertFrom
        ///  
        ///  
        public override object ConvertFrom(
            ITypeDescriptorContext td, 
            CultureInfo cultureInfo,
            object value)
        {
            string stringValue = value as string; 

            // Override the converter for sentinel values 
            if (stringValue != null) 
            {
                stringValue = stringValue.Trim(); 
                if (stringValue == "Automatic")
                {
                    return Duration.Automatic;
                } 
                else if (stringValue == "Forever")
                { 
                    return Duration.Forever; 
                }
            } 

            TimeSpan duration = TimeSpan.Zero;
            if(_timeSpanConverter == null)
            { 
                 _timeSpanConverter = new TimeSpanConverter();
            } 
            duration = (TimeSpan)_timeSpanConverter.ConvertFrom(td, cultureInfo, value); 
            return new Duration(duration);
        } 

        /// 
        /// TypeConverter method implementation.
        ///  
        /// ITypeDescriptorContext
        /// current culture (see CLR specs) 
        /// value to convert from 
        /// Type to convert to
        /// converted value 
        /// 
        ///
        ///     Critical: calls InstanceDescriptor ctor which LinkDemands
        ///     PublicOK: can only make an InstanceDescriptor for Duration, not an arbitrary class 
        ///
        [SecurityCritical] 
        public override object ConvertTo( 
            ITypeDescriptorContext context,
            CultureInfo cultureInfo, 
            object value,
            Type destinationType)
        {
            if (destinationType != null && value is Duration) 
            {
                Duration durationValue = (Duration)value; 
 
                if (destinationType == typeof(InstanceDescriptor))
                { 
                    MemberInfo mi;

                    if (durationValue.HasTimeSpan)
                    { 
                        mi = typeof(Duration).GetConstructor(new Type[] { typeof(TimeSpan) });
 
                        return new InstanceDescriptor(mi, new object[] { durationValue.TimeSpan }); 
                    }
                    else if (durationValue == Duration.Forever) 
                    {
                        mi = typeof(Duration).GetProperty("Forever");

                        return new InstanceDescriptor(mi, null); 
                    }
                    else 
                    { 
                        Debug.Assert(durationValue == Duration.Automatic);  // Only other legal duration type
 
                        mi = typeof(Duration).GetProperty("Automatic");

                        return new InstanceDescriptor(mi, null);
                    } 
                }
                else if (destinationType == typeof(string)) 
                { 
                    return durationValue.ToString();
                } 
            }

            // Pass unhandled cases to base class (which will throw exceptions for null value or destinationType.)
            return base.ConvertTo(context, cultureInfo, value, destinationType); 
        }
        private static TimeSpanConverter _timeSpanConverter; 
    } 
}

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

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