How to specify a WCF known type in config that is generic?

Question

I have a type, let\'s call it Data. I also have a WCF service contract that accepts a type (lets call it Wrapper) with a property of type

Answer 1

A generic type is instantiable from a string, if the string follows this pattern: Class name followed by a "`" character, followed by the number of type parameters(in this case it's 1), followed by the type parameters enclosed within "[]", and using comma as type parameter separator.

<configuration>
  <system.runtime.serialization>
    <dataContractSerializer>
      <declaredTypes>
        <add type="Wrapper, TheirAssembly">
          <!-- this syntax is all good -->
          <knownType type="Data`1[System.Int32], MyAssembly"/>
          <knownType type="Data`1[System.Int64], MyAssembly"/>
        </add>
      </declaredTypes>
    </dataContractSerializer>
  </system.runtime.serialization>
</configuration>

Edit: I might also add, that if assembly information needs to be specified for the type parameters(althoug it's not the case for stuff in mscorlib), then nested "[]" is used.

<knownType type="Data`1[[System.Int32, mscorlib]], MyAssembly"/>

Edit: You can customize names of generic types in data contracts, using the string format pattern.

[DataContract(Name = "Data{0}")]
public class Data<TKey>
{...}

By default, the name generated for the Data<Int32> type is something like "DataOfInt32HJ67AK7Y", where "HJ67AK7Y" is a hash generated from the string "urn:default", or the namespace of your class, if you have any. But "Data{0}" would give it the name "DataInt32".

More here. Have a look at the "Customizing Data Contract Names for Generic Types" part down the page.

Answer 2

From here...

Known types can also be defined in config as shown below.

<configuration>
  <system.runtime.serialization>
    <dataContractSerializer>
      <declaredTypes>
         <add type="MyCompany.Library.Shape`1,
              MyAssembly, Version=2.0.0.0, Culture=neutral,
              PublicKeyToken=XXXXXX, processorArchitecture=MSIL">
            <knownType type="MyCompany.Library.Circle`1,
                       MyAssembly, Version=2.0.0.0, Culture=neutral,
                       PublicKeyToken=XXXXXX, processorArchitecture=MSIL">
                    <parameter index="0"/>
            </knownType>
         </add>
      </declaredTypes>
    </dataContractSerializer>
  </system.runtime.serialization>
</configuration>

The above config specifies that the generic parameter for Circle is the same as the generic parameter for the declared type Shape. The config allows the definition of known type of arbitrary complexity. For example if it is needed to define Circle< Dictionary< string, T >> as the known type of Shape< T > (of course this is purely academic) it can be done as follows.

<configuration>
  <system.runtime.serialization>
    <dataContractSerializer>
      <declaredTypes>
         <add type="MyCompany.Library.Shape`1,
              MyAssembly, Version=2.0.0.0, Culture=neutral,
              PublicKeyToken=XXXXXX, processorArchitecture=MSIL">
            <knownType type="MyCompany.Library.Circle`1,
                       MyAssembly, Version=2.0.0.0, Culture=neutral,
                       PublicKeyToken=XXXXXX, processorArchitecture=MSIL">
                   <parameter type="System.Collections.Generic.Dictionary`2">
                      <parameter type="System.String"/>
                      <parameter index="0"/>
                   </parameter>                
            </knownType>
         </add>
      </declaredTypes>
    </dataContractSerializer>
  </system.runtime.serialization>
</configuration>

Note the use config element “parameter” with the attributes ‘type’ and ‘index’.