ContextTokenTypeConverter.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx35 / System.WorkflowServices / System / Workflow / Activities / ContextTokenTypeConverter.cs / 1305376 / ContextTokenTypeConverter.cs
                        
                        
                            //---------------------------------------------------------------- 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//---------------------------------------------------------------
namespace System.Workflow.Activities
{ 
    using System;
    using System.Xml; 
    using System.ComponentModel; 
    using System.ComponentModel.Design;
    using System.ComponentModel.Design.Serialization; 
    using System.Reflection;
    using System.Collections;
    using System.Collections.Generic;
    using System.Collections.Specialized; 
    using System.Diagnostics;
    using System.Runtime.Serialization; 
    using System.Workflow.ComponentModel; 
    using System.Workflow.ComponentModel.Design;
    using System.Workflow.ComponentModel.Serialization; 
    using System.Workflow.Runtime;
    using System.Globalization;

    internal sealed class ContextTokenTypeConverter : ExpandableObjectConverter 
    {
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) 
        { 
            return (sourceType == typeof(string));
        } 

        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            return (destinationType == typeof(string)); 
        }
 
        public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value) 
        {
            object convertedValue = null; 
            string contextName = value as String;
            if (!String.IsNullOrEmpty(contextName))
            {
                foreach (object obj in GetStandardValues(context)) 
                {
                    ContextToken contextToken = obj as ContextToken; 
                    if (contextToken != null && contextToken.Name == contextName) 
                    {
                        convertedValue = contextToken; 
                        break;
                    }
                }
 
                if (convertedValue == null)
                { 
                    convertedValue = new ContextToken(contextName); 
                }
            } 

            return convertedValue;
        }
 
        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        { 
            object convertedValue = null; 
            ContextToken contextToken = value as ContextToken;
            if (destinationType == typeof(string) && contextToken != null) 
            {
                convertedValue = contextToken.Name;
            }
            return convertedValue; 
        }
 
        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes) 
        {
            PropertyDescriptorCollection properties = base.GetProperties(context, value, attributes); 
            ArrayList props = new ArrayList(properties);
            return new PropertyDescriptorCollection((PropertyDescriptor[]) props.ToArray(typeof(PropertyDescriptor)));
        }
 
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        { 
            ArrayList values = new ArrayList(); 
            Activity activity = context.Instance as Activity;
            if (activity != null) 
            {
                foreach (Activity preceedingActivity in GetPreceedingActivities(activity))
                {
                    PropertyDescriptor contextTokenProperty = TypeDescriptor.GetProperties(preceedingActivity)["ContextToken"] as PropertyDescriptor; 
                    if (contextTokenProperty != null)
                    { 
                        ContextToken contextToken = contextTokenProperty.GetValue(preceedingActivity) as ContextToken; 
                        if (contextToken != null && !values.Contains(contextToken))
                        { 
                            values.Add(contextToken);
                        }
                    }
                } 
            }
            return new StandardValuesCollection(values); 
        } 

        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) 
        {
            return false;
        }
 
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
        { 
            return true; 
        }
 
        private IEnumerable GetContainedActivities(CompositeActivity activity)
        {
            if (!activity.Enabled)
            { 
                yield break;
            } 
 
            foreach (Activity containedActivity in activity.Activities)
            { 
                if (containedActivity.Enabled)
                {
                    yield return containedActivity;
 
                    if (containedActivity is CompositeActivity)
                    { 
                        foreach (Activity nestedActivity in GetContainedActivities((CompositeActivity) containedActivity)) 
                        {
                            if (nestedActivity.Enabled) 
                            {
                                yield return nestedActivity;
                            }
                        } 
                    }
                } 
            } 
            yield break;
        } 

        private IEnumerable GetPreceedingActivities(Activity startActivity)
        {
            Activity currentActivity = null; 
            Stack activityStack = new Stack();
            activityStack.Push(startActivity); 
 
            while ((currentActivity = activityStack.Pop()) != null)
            { 
                if (currentActivity.Parent != null)
                {
                    foreach (Activity siblingActivity in currentActivity.Parent.Activities)
                    { 
                        if (siblingActivity == currentActivity)
                        { 
                            continue; 
                        }
 
                        if (siblingActivity.Enabled)
                        {
                            yield return siblingActivity;
 
                            if (siblingActivity is CompositeActivity)
                            { 
                                foreach (Activity containedActivity in GetContainedActivities((CompositeActivity) siblingActivity)) 
                                {
                                    yield return containedActivity; 
                                }
                            }
                        }
                    } 
                }
                activityStack.Push(currentActivity.Parent); 
            } 
            yield break;
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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ContextTokenTypeConverter.cs source code in C# .NET

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