R – workflow xoml file cannot deserialized after mapping XML namespace to a CLR namespace

networkflowworkflow-foundation

I added the following attribute to the assemblyinfo.cs file in the activities project:

using System.Workflow.ComponentModel.Serialization;
[assembly:XmlnsDefinition("http://Myproject/MyActivitiesLib", "MyActivitiesLib")]*

Also in my workflow runtime initilize methold, I loaded assemblyreference as following:

using (WorkflowRuntime runtime    = new WorkflowRuntime())
{
    TypeProvider provider = new TypeProvider(runtime);
    provider.AddAssemblyReference("MyActivitiesLib.dll");
    runtime.AddService(provider);
    //start workflow
    ...
}

now I can serialize workflow to xoml file and assembly in workflow xoml file, the XML namespace in match the changes as:
xmlns:msdn="http://Myproject/MyActivitiesLib"

however when I try to deserialize the file , I got an loaderror as this:

Cannot open a designer for the file because the class within it does not inherit from a class that can be visually designed

Best Answer

Not quite sure what your problem is but I wrote a blog post some time ago about custom activities and pure XOML workflows that might help you. You can find it here.

Also to troubleshoot this I would suggest trying to remove activities and seeing when you can open the XOML file in the designer. That way you can pinpoint the offending activity and that will heft solving the problem.

Related Solutions

C# – How to use workflows with older versions of activity libraries in (rehosted) workflow designer

It turned out that the TypeProviders are not a reliable way to resolve assembly references that are missing for the workflow rendering (and accessing the tracking information for old activities etc.). The problem is not only that they don't work for SqlTrackingService, but also that to be able to pass an assembly into the TypeProvider it has to be loaded into the AppDomain. Having multiple versions of the same assembly in the AppDomain causes crazy things to happen, so it was absolutely necessary to avoid it.

Although it is not possible to unload an assembly from an AppDomain once it's been loaded, it is possible to create an isolated AppDomain which loads the older version of assemblies when necessary (I've done this registering to the AssemblyResolve event of the AppDomain) and then simply unload the whole AppDomain when the work is done. For example of how this can be done see related question.

Now I'm happily showing diagrams from different versions of activity libraries without any problems ;)

C# – DataContractSerializer – change namespace and deserialize file bound to old namespace

One possible way is to wrap the reader used by the serializer in a reader which maps the old namespace to the new one, as shown below. A lot of code, but mostly trivial.

public class StackOverflow_11092274
{
    const string XML = @"<?xml version=""1.0"" encoding=""utf-8""?> 
<Data xmlns:i=""http://www.w3.org/2001/XMLSchema-instance"" xmlns=""http://schemas.datacontract.org/2004/07/XYZ""> 
   <Prop1>StringValue</Prop1> 
   <Prop2>11</Prop2> 
</Data>";

    [DataContract(Name = "Data", Namespace = "")]
    public class Data
    {
        [DataMember(Order = 1)]
        public string Prop1 { get; set; }

        [DataMember(Order = 2)]
        public int Prop2 { get; set; }
    }

    public class MyReader : XmlReader
    {
        XmlReader inner;
        public MyReader(XmlReader inner)
        {
            this.inner = inner;
        }

        public override int AttributeCount
        {
            get { return inner.AttributeCount; }
        }

        public override string BaseURI
        {
            get { return inner.BaseURI; }
        }

        public override void Close()
        {
            inner.Close();
        }

        public override int Depth
        {
            get { return inner.Depth; }
        }

        public override bool EOF
        {
            get { return inner.EOF; }
        }

        public override string GetAttribute(int i)
        {
            return inner.GetAttribute(i);
        }

        public override string GetAttribute(string name, string namespaceURI)
        {
            return inner.GetAttribute(name, namespaceURI);
        }

        public override string GetAttribute(string name)
        {
            return inner.GetAttribute(name);
        }

        public override bool IsEmptyElement
        {
            get { return inner.IsEmptyElement; }
        }

        public override string LocalName
        {
            get { return inner.LocalName; }
        }

        public override string LookupNamespace(string prefix)
        {
            return inner.LookupNamespace(prefix);
        }

        public override bool MoveToAttribute(string name, string ns)
        {
            return inner.MoveToAttribute(name, ns);
        }

        public override bool MoveToAttribute(string name)
        {
            return inner.MoveToAttribute(name);
        }

        public override bool MoveToElement()
        {
            return inner.MoveToElement();
        }

        public override bool MoveToFirstAttribute()
        {
            return inner.MoveToFirstAttribute();
        }

        public override bool MoveToNextAttribute()
        {
            return inner.MoveToNextAttribute();
        }

        public override XmlNameTable NameTable
        {
            get { return inner.NameTable; }
        }

        public override string NamespaceURI
        {
            get
            {
                if (inner.NamespaceURI == "http://schemas.datacontract.org/2004/07/XYZ")
                {
                    return "";
                }
                else
                {
                    return inner.NamespaceURI;
                }
            }
        }

        public override XmlNodeType NodeType
        {
            get { return inner.NodeType; }
        }

        public override string Prefix
        {
            get { return inner.Prefix; }
        }

        public override bool Read()
        {
            return inner.Read();
        }

        public override bool ReadAttributeValue()
        {
            return inner.ReadAttributeValue();
        }

        public override ReadState ReadState
        {
            get { return inner.ReadState; }
        }

        public override void ResolveEntity()
        {
            inner.ResolveEntity();
        }

        public override string Value
        {
            get { return inner.Value; }
        }
    }

    public static void Test()
    {
        DataContractSerializer dcs = new DataContractSerializer(typeof(Data));
        MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(XML));
        try
        {
            XmlReader r = XmlReader.Create(ms);
            XmlReader my = new MyReader(r);
            Data d = (Data)dcs.ReadObject(my);
            Console.WriteLine("Data[Prop1={0},Prop2={1}]", d.Prop1, d.Prop2);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
    }
}

Best Answer

Related Solutions

C# – How to use workflows with older versions of activity libraries in (rehosted) workflow designer

C# – DataContractSerializer – change namespace and deserialize file bound to old namespace

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