Dynamic data type in WCF services (Using KnownType Attribute)

Here i am going to explain how to return dynamic or runtime data type from WCF services,
In WCF you find a attribute named KnowType, this attribute is for telling the service that what is the possible return type of the method so thatWCF create a proxy of these types in refrence.cs file.

How to Use :-
You need to create a base type class as given below BaseDataType and define KnowType attribute here as the possible types of this base type class like type of User and type of Division etc.

[DataContract]
[Serializable]
[KnownType(typeof(User))]
[KnownType(typeof(Division))]
[KnownType(typeof(Workgroup))]
[KnownType(typeof(Document))]
[KnownType(typeof(GlobalIndexField))]
[KnownType(typeof(IndexFieldGroup))]
[KnownType(typeof(FileFormat))]
[KnownType(typeof(FileOperation))]
[KnownType(typeof(Platform))]
[KnownType(typeof(ProfileProgram))]
[KnownType(typeof(UserProfile))]
[KnownType(typeof(Annotation))]
[KnownType(typeof(Workflow))]
[KnownType(typeof(ReproDevice))]
[KnownType(typeof(Media))]
[KnownType(typeof(ProgramName))]
public abstract class BaseDataType
{

}

Then created a class that contains BaseDataType as given DynamicData below or you can direct return BaseDataType from your operation contract.

[DataContract]
[Serializable]
 public class DynamicData
 {
     public IList<BaseDataType> Data { getset; }   
 }


Each and every class that you need to return from service (need to include in dynamic DataContract) must be inherited with BaseDataType (must be type of BaseDataType).

 [DataContract]
  [Serializable]
  public class User : BaseDataType
  {

 [DataContract]
  [Serializable]
  public class Division : BaseDataType
  {

 [DataContract]
  [Serializable]
  public class Workgroup : BaseDataType
  {


Create an operation contract that returns dynamic type (i.e direct BaseDataType or DynamicData type) write your functionality here return any dynamic data that you already defined in the KnowType attribute and map it with the BaseDataType as given below.

public DynamicData SearchInIndex(AppEnums.GlobalSearchType searchType,string searchKey)
{
    dynamic dynamicResult;
    switch (searchType)
    {
        case AppEnums.GlobalSearchType.Database:
            dynamicResult= SearchInIndexByDatabase(searchKey);
            break;
        case AppEnums.GlobalSearchType.ElasticSearch:
            dynamicResult= SearchInIndexByElasticSearch(searchKey);
            break;
        default:
            throw new NotImplementedException();
    }
    return MapData(dynamicResult);

}

 public DynamicData MapData(dynamic data)
 {
    DynamicData dynamicResult = new DynamicData();
    dynamicResult.Data = new List<BaseDataType>();
    foreach (var item in data)
    {
       dynamicResult.Data.Add((BaseDataType)item);
    }
    return dynamicResult;
 }

you can directly return BaseDataType from the operation contract.
public List<BaseDataType> SearchInIndex(AppEnums.GlobalSearchType searchType,string searchKey)
{
    dynamic dynamicResult;
    switch (searchType)
    {
        case AppEnums.GlobalSearchType.Database:
            dynamicResult= SearchInIndexByDatabase(searchKey);
            break;
        case AppEnums.GlobalSearchType.ElasticSearch:
            dynamicResult= SearchInIndexByElasticSearch(searchKey);
            break;
        default:
            throw new NotImplementedException();
    }
    return MapData(dynamicResult);

}

 public List<BaseDataType> MapData(dynamic data)
 {
    List<BaseDataType> dynamicResult = new List<BaseDataType>();
    foreach (var item in data)
    {
       dynamicResult.Add((BaseDataType)item);
    }
    return dynamicResult;
 }



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