CODEWITHSUNDEEP
c#wcfserializationtree.net-4.5
Killnine
Killnine

Reputation: 5900

WCF object serialization woes

I have a basic object that I am sending over the wire via WCF. It's intended purpose it to help populate a Tree of data. Here's the basic structure:

[DataContract]
public class ProjectTreeNode
{
    private IList<ProjectTreeNode> _children = new List<ProjectTreeNode>();

    [DataMember]
    public int ParentCategoryID { get; set; }

    [DataMember]
    public bool IsProject { get; set; }

    [DataMember]
    public int ProjectID { get; set; }

    [DataMember]
    public string Description { get; set; }

    [DataMember]
    public ProjectTreeNode Parent { get; set; }

    [DataMember]
    public IList<ProjectTreeNode> Children
    {
        get { return _children; }
        set { _children = value; }
    }

    public ProjectTreeNode() { }

    public ProjectTreeNode(string description, int parentCategoryID, IEnumerable<ProjectDto> projectChildren)
    {
        Description = description;
        ParentCategoryID = parentCategoryID;

        foreach (var project in projectChildren)
        {
            Children.Add(new ProjectTreeNode { Description = project.Description, IsProject = true, ProjectID = project.ProjectID, Parent = this });
        }
    }
}

Unfortunately, any time I try and retrieve a ProjectTreeNode that has Children, I get errors from WCF (CommunicationException, but I am convinced its actually masking a serialization problem).

So this works fine:

public ProjectTreeNode TestNode()
{
    return new ProjectTreeNode("Test Node", -1, new ProjectDto[0]);
}

But this receives an exception on the client side:

public ProjectTreeNode TestNode()
{
    return new ProjectTreeNode("Test Node", -1, new[] { new ProjectDto { CategoryCombinationID = 123, Description = "Blah", ProjectID = 10} });
}

I know that constructors are stripped out when transferred over the wire, but I am confused why a complete object would still blow up in my face like this.

Upvotes: 2

Views: 173

Answers (1)

Belogix
Belogix

Reputation: 8147

This is because you have a circular reference. I.e. Parent has link to child and child has link to parent. So you are right that this is a serialisation issue - when the object is serialised you will get exceptions as you recurse for infinity.

A simple fix is to mark the DataContract as a Reference like so:

[DataContract(IsReference=true)]
public class ProjectTreeNode
{
    // ...
}

Upvotes: 2

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