WorkflowViewService.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / View / WorkflowViewService.cs / 1305376 / WorkflowViewService.cs
                        
                        
                            //---------------------------------------------------------------- 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//---------------------------------------------------------------

namespace System.Activities.Presentation.View 
{
    using System.Activities.Presentation; 
    using System.Activities.Presentation.Internal.PropertyEditing; 
    using System.Activities.Presentation.Model;
    using System.Activities.Presentation.Services; 
    using System.Activities.XamlIntegration;
    using System.ComponentModel;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization; 
    using System.Runtime;
    using System.ServiceModel.Activities; 
    using System.Windows; 
    using System.Windows.Controls;
    using System.Windows.Media; 
using System.Collections.Generic;

    [Fx.Tag.XamlVisible(false)]
    public class WorkflowViewService : ViewService 
    {
        EditingContext context; 
 
        static Dictionary DelayedRegistrations = new Dictionary();
 
        internal static void AddDelayedDesignerRegistration(string typeName, Action registration)
        {
            DelayedRegistrations[typeName] = registration;
        } 

        static void InvokeDelayedRegistration(string typeName) 
        { 
            Action registration = null;
            if (DelayedRegistrations.TryGetValue(typeName, out registration)) 
            {
                DelayedRegistrations.Remove(typeName);
                registration();
            } 
        }
 
        public WorkflowViewService(EditingContext context) 
        {
            Fx.Assert(context != null, "The passed in EditingContext is null"); 
            this.context = context;
        }
        internal event ViewChangedEventHandler ViewChanged;
 
        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
            Justification="Catch all exceptions to prevent crash and always return the error view of the designer with the error message")] 
        [SuppressMessage("Reliability", "Reliability108:IsFatalRule", 
            Justification = "Catch all exceptions to prevent crash and always return the error view of the designer with the error message")]
        public WorkflowViewElement GetViewElement(ModelItem modelItem) 
        {
            WorkflowViewElement viewElement = null;
            string errorString = string.Empty;
            if (modelItem == null) 
            {
                return null; 
            } 

            try 
            {
                // try to make one from the type specified in Designer attribute.
                // reuse existing views that are not currently parented
                if (modelItem.View != null && ((WorkflowViewElement)modelItem.View).Parent == null) 
                {
                    viewElement = (WorkflowViewElement)modelItem.View; 
                } 
                else
                { 
                    viewElement = CreateViewElement(modelItem);
                }

                // now we successfully got a viewElement, lets initialize it with ModelItem; 
                if (viewElement != null)
                { 
                    viewElement.Context = this.context; 
                    viewElement.ModelItem = modelItem;
                    ((IModelTreeItem)modelItem).SetCurrentView(viewElement); 
                    viewElement.DataContext = viewElement;

                    // Generate an event that we created a new view element.  This could be used by
                    // the Debugger Service to insert a breakpoint on the view element. 
                    if (this.ViewChanged != null)
                    { 
                        this.ViewChanged(this, new ViewChangedEventArgs(viewElement)); 
                    }
                } 
            }
            // never crash here
            // always report error to the customer.
            catch (Exception e) 
            {
                errorString = e.ToString(); 
            } 
            if (viewElement == null || !(string.IsNullOrEmpty(errorString)))
            { 
                viewElement = GenerateErrorElement(modelItem, errorString);
            }
            return viewElement;
        } 

        internal static void ShowErrorInViewElement(WorkflowViewElement errorElement, string windowText, string toolTipText) 
        { 
            Grid errorGrid = new Grid();
            errorGrid.Background = Brushes.Red; 
            errorGrid.Margin = new Thickness(20.0);
            TextBlock text = new TextBlock();
            text.Text = windowText;
            text.Foreground = SystemColors.WindowBrush; 
            errorGrid.Children.Add(text);
            errorGrid.ToolTip = toolTipText; 
            errorElement.Content = errorGrid; 
        }
 
        private WorkflowViewElement GenerateErrorElement(ModelItem modelItem, string errorString)
        {
            WorkflowViewElement errorElement = new WorkflowViewElement();
            string errorText = string.Format(CultureInfo.CurrentCulture, SR.CouldNotGenerateView, modelItem.ItemType.Name); 
            ShowErrorInViewElement(errorElement, errorText, errorString);
            errorElement.Context = this.context; 
            errorElement.ModelItem = modelItem; 
            ((IModelTreeItem)modelItem).SetCurrentView(errorElement);
            errorElement.DataContext = errorElement; 
            return errorElement;
        }

        DesignerAttribute GetDesignerAttribute(Type type) 
        {
            DesignerAttribute designerAttribute = null; 
            //do not return designers for IValueSerializableExpression (i.e. VisualBasicValue or VisualBasicReference 
            if (!typeof(IValueSerializableExpression).IsAssignableFrom(type))
            { 
                designerAttribute = GetAttribute(type);
            }
            return designerAttribute;
        } 

        internal static T GetAttribute(Type type) where T : Attribute 
        { 
            T attribute = ExtensibilityAccessor.GetAttribute(type);
            if (attribute == null && type.IsGenericType) 
            {
                attribute = ExtensibilityAccessor.GetAttribute(type.GetGenericTypeDefinition());
            }
            return attribute; 
        }
 
        //Returns the designer type based on the DesignerAttribute associated with the passed in type. 
        internal Type GetDesignerType(Type type)
        { 
            return GetDesignerType(type, false);
        }

        internal Type GetDesignerType(Type type, bool throwOnFailure) 
        {
            Type designerType = null; 
            // Run delayed metadataregistrations before trying to get an attribute. 
            InvokeDelayedRegistration(type.FullName);
            // Try to identify a designer using the DesignerAttribute, either on the type or from MetaDataStore 
            DesignerAttribute designerAttribute = GetDesignerAttribute(type);
            if (designerAttribute != null && !String.IsNullOrEmpty(designerAttribute.DesignerTypeName))
            {
                designerType = Type.GetType(designerAttribute.DesignerTypeName, throwOnFailure); 

                //if we have generic activity, check if there is a designer defined at type definition i.e. Assign, 
                //rather then using a defualt one (which happens to be ActivityDesigner) 
                if (type.IsGenericType && Type.Equals(designerType, typeof(ActivityDesigner)))
                { 
                    Type genericType = type.GetGenericTypeDefinition();
                    DesignerAttribute genericDesignerAttribute =
                        TypeDescriptor.GetAttributes(genericType)[typeof(DesignerAttribute)] as DesignerAttribute;
                    designerType = 
                        (null == genericDesignerAttribute ?
                        designerType : Type.GetType(genericDesignerAttribute.DesignerTypeName, throwOnFailure)); 
                } 
            }
            return designerType; 
        }

        protected WorkflowViewElement CreateViewElement(ModelItem modelItem)
        { 
            Fx.Assert(modelItem != null, "The passed in ModelItem is null");
            WorkflowViewElement viewElement = null; 
 
            Type designerType = GetDesignerType(modelItem.ItemType, true);
 
            if(designerType != null && typeof(WorkflowViewElement).IsAssignableFrom(designerType))
            {
                viewElement = (WorkflowViewElement)Activator.CreateInstance(designerType);
            } 
            return viewElement;
        } 
 
        public override ModelItem GetModel(DependencyObject view)
        { 
            if (view == null)
            {
                throw FxTrace.Exception.AsError(new ArgumentNullException("view"));
            } 

            if (view is WorkflowViewElement) 
            { 
                return ((WorkflowViewElement)view).ModelItem;
            } 

            Fx.Assert("we should know if somebody is trying to get model item from thing other than WorkflowViewElement");
            return null;
        } 

        public override DependencyObject GetView(ModelItem model) 
        { 
            return GetViewElement(model);
        } 

        internal bool ShouldAppearOnBreadCrumb(ModelItem modelItem, bool checkIfCanBeMadeRoot)
        {
            bool shouldAppearOnBreadCrumb = false; 
            if (modelItem != null)
            { 
                Type designerType = this.GetDesignerType(modelItem.ItemType); 
                if (null != designerType)
                { 
                    if (checkIfCanBeMadeRoot)
                    {
                        ActivityDesignerOptionsAttribute options = WorkflowViewService.GetAttribute(modelItem.ItemType);
                        shouldAppearOnBreadCrumb = (typeof(WorkflowViewElement).IsAssignableFrom(designerType) && 
                                                   typeof(ActivityDesigner) != designerType &&
                                                   typeof(WorkflowService) != designerType && 
                                                   (options == null || options.AllowDrillIn)); 
                    }
                    else 
                    {
                        shouldAppearOnBreadCrumb = typeof(WorkflowViewElement).IsAssignableFrom(designerType);
                    }
                } 
            }
            return shouldAppearOnBreadCrumb; 
 
        }
 
        internal delegate void ViewChangedEventHandler(object sender, ViewChangedEventArgs eventArgs);

        internal class ViewChangedEventArgs : EventArgs
        { 
            WorkflowViewElement addedElement;
 
            public ViewChangedEventArgs(WorkflowViewElement addedElement) 
            {
                this.addedElement = addedElement; 
            }

            public WorkflowViewElement AddedElement
            { 
                get { return this.addedElement; }
            } 
        } 
    }
} 

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

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