The underlying connection was closed: The connection was closed unexpectedly

Question

This exception is consistently thrown on a SOAP Request which takes almost three minutes to receive and is 2.25 megs in size.

When scouring the web I find all sorts

Answer 1

I hope it's not too late for answering this question.

Try adding the following attribute on the definition of your contract interface:

[ServiceKnownType(typeof(ReturnClass))]

For more generic solution that allows returning polymorphic classes please refer to this post: http://www.goeleven.com/blog/entryDetail.aspx?entry=45

Answer 2

I've got the same issue, and after deep investigations I found this article:

Merrick Chaffer's Blog

It was all related to setting the "dataContractSerializer" for both client and server. Hope this to be helpful.

Answer 3

i got this error because my datatransfereobjects refered to each other in an recursive manner.

For example:

Customer-> (has) -> Rating Rating-> (belong to) -> Customer

so you have to remove cycles.

[DataContract]
public class Rating
{
    private Customer _customer;
    //[DataMember] // <-  EITHER HERE 
    public Customer Customer
    {
        get { return _customer; }
        set { _customer = value; }
    }
}


[DataContract]
public class Customer
{
    private long _customerID;
    [DataMember]
    public long CustomerID
    {
        get { return _customerID; }
        set { _customerID = value; }
    }

    [DataMember] // <- OR HERE
    public Rating Rating
    {
        get { return _rating; }
        set { _rating = value; }
    }
}

Answer 4

For WCF with EF, just add the following code in the context class.

base.Configuration.ProxyCreationEnabled = false;