DesignTimeXamlWriter.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 / Xaml / DesignTimeXamlWriter.cs / 1305376 / DesignTimeXamlWriter.cs
                        
                        
                            //---------------------------------------------------------------- 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//---------------------------------------------------------------

namespace System.Activities.Presentation.Xaml 
{
    using System.Collections.Generic; 
    using System.Globalization; 
    using System.IO;
    using System.Xaml; 
    using System.Xml;

    class DesignTimeXamlWriter : XamlXmlWriter
    { 
        //namespaces to ignore (don't load assembilies for) at root node
        HashSet namespacesToIgnore; 
 
        //namespaces we've seen at root level, we use this to figure out appropriate alias for MC namespace
        HashSet rootLevelNamespaces; 

        // for duplicate namespace filtering (happens if we're using the local assembly to compile itself)
        HashSet emittedNamespacesInLocalAssembly;
 
        //For namespace defined in local assembly with assembly info in namespace declaration, we'll strip out the assembly info
        //and hold the namespace temporarily. Before writing the start object, we'll check whether the short version gets written 
        //as a separate declaration, if not, we write it out. 
        List localNamespacesWithAssemblyInfo;
 
        bool hasWrittenObject;
        WorkflowDesignerXamlSchemaContext schemaContext;

        public DesignTimeXamlWriter(TextWriter textWriter, WorkflowDesignerXamlSchemaContext context) 
            : base(XmlWriter.Create(textWriter, new XmlWriterSettings { Indent = true, OmitXmlDeclaration = true }), context,
                // Setting AssumeValidInput to true allows to save a document even if it has duplicate members 
                new XamlXmlWriterSettings { AssumeValidInput = true }) 
        {
            this.namespacesToIgnore = new HashSet(); 
            this.rootLevelNamespaces = new HashSet();
            this.schemaContext = context;
        }
 
        public override void WriteNamespace(NamespaceDeclaration namespaceDeclaration)
        { 
            if (!this.hasWrittenObject) 
            {
                //we need to track every namespace alias appeared in root element to figure out right alias for MC namespace 
                this.rootLevelNamespaces.Add(namespaceDeclaration.Prefix);

                //Remember namespaces needed to be ignored at top level so we will add ignore attribute for them when we write start object
                if (NameSpaces.ShouldIgnore(namespaceDeclaration.Namespace)) 
                {
                    this.namespacesToIgnore.Add(namespaceDeclaration.Prefix); 
                } 
            }
 
            EmitNamespace(namespaceDeclaration);
        }

        void EmitNamespace(NamespaceDeclaration namespaceDeclaration) 
        {
            // Write the namespace, filtering for duplicates in the local assembly because VS might be using it to compile itself. 
 
            if (schemaContext.IsClrNamespaceWithNoAssembly(namespaceDeclaration.Namespace))
            { 
                // Might still need to trim a semicolon, even though it shouldn't strictly be there.
                string nonassemblyQualifedNamespace = namespaceDeclaration.Namespace;
                if (nonassemblyQualifedNamespace[nonassemblyQualifedNamespace.Length - 1] == ';')
                { 
                    nonassemblyQualifedNamespace = nonassemblyQualifedNamespace.Substring(0, nonassemblyQualifedNamespace.Length - 1);
                    namespaceDeclaration = new NamespaceDeclaration(nonassemblyQualifedNamespace, namespaceDeclaration.Prefix); 
                } 
                EmitLocalNamespace(namespaceDeclaration);
            } 
            else if (schemaContext.IsClrNamespaceInLocalAssembly(namespaceDeclaration.Namespace))
            {
                string nonassemblyQualifedNamespace = schemaContext.TrimLocalAssembly(namespaceDeclaration.Namespace);
                namespaceDeclaration = new NamespaceDeclaration(nonassemblyQualifedNamespace, namespaceDeclaration.Prefix); 
                if (this.localNamespacesWithAssemblyInfo == null)
                { 
                    this.localNamespacesWithAssemblyInfo = new List(); 
                }
                this.localNamespacesWithAssemblyInfo.Add(namespaceDeclaration); 
            }
            else
            {
                base.WriteNamespace(namespaceDeclaration); 
            }
        } 
 
        void EmitLocalNamespace(NamespaceDeclaration namespaceDeclaration)
        { 
            if (this.emittedNamespacesInLocalAssembly == null) // lazy initialization
            {
                this.emittedNamespacesInLocalAssembly = new HashSet();
            } 

            // Write the namespace only once. Add() returns false if it was already there. 
            if (this.emittedNamespacesInLocalAssembly.Add(namespaceDeclaration.Namespace)) 
            {
                base.WriteNamespace(namespaceDeclaration); 
            }
        }

 
        public override void WriteStartObject(XamlType type)
        { 
            // this is the top-level object 
            if (!this.hasWrittenObject)
            { 
                // we need to write MC namespace if any namespaces need to be ignored
                if (this.namespacesToIgnore.Count > 0)
                {
                    string mcNamespaceAlias = GenerateNamespaceAlias(NameSpaces.McPrefix); 
                    this.WriteNamespace(new NamespaceDeclaration(NameSpaces.Mc, mcNamespaceAlias));
                } 
 
                if (this.localNamespacesWithAssemblyInfo != null)
                { 
                    foreach (NamespaceDeclaration xamlNamespace in this.localNamespacesWithAssemblyInfo)
                    {
                        if ((this.emittedNamespacesInLocalAssembly == null) || (!this.emittedNamespacesInLocalAssembly.Contains(xamlNamespace.Namespace)))
                        { 
                            base.WriteNamespace(xamlNamespace);
                        } 
                    } 
                }
            } 

            base.WriteStartObject(type);

            if (!this.hasWrittenObject) 
            {
                // we need to add Ignore attribute for all namespaces which we don't want to load assemblies for 
                // this has to be done after WriteStartObject 
                if (this.namespacesToIgnore.Count > 0)
                { 
                    foreach (string ns in this.namespacesToIgnore)
                    {
                        XamlDirective ignorable = new XamlDirective(NameSpaces.Mc, "Ignorable");
                        base.WriteStartMember(ignorable); 
                        base.WriteValue(ns);
                        base.WriteEndMember(); 
                    } 

                    this.namespacesToIgnore.Clear(); 
                }
                this.hasWrittenObject = true;
            }
        } 

        string GenerateNamespaceAlias(string prefix) 
        { 
            string aliasPostfix = string.Empty;
            //try "mc"~"mc1000" first 
            for (int i = 1; i <= 1000; i++)
            {
                string mcAlias = prefix + aliasPostfix;
                if (!this.rootLevelNamespaces.Contains(mcAlias)) 
                {
                    return mcAlias; 
                } 
                aliasPostfix = i.ToString(CultureInfo.InvariantCulture);
            } 

            //roll the dice
            return prefix + Guid.NewGuid().ToString();
        } 
    }
} 

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

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