How to exclude data members from JSON/XML serialization during runtime

Question

I have a list of strings in my web.config that describes the names of the model members (generated by Entity Framework) that are allowed to be serialized in my web api.
How do I eg set the [IgnoreDataMember] attribute during runtime?
The idea is, that not all the data should be exposed and the configuration what should be exposed, should be configurable without recompilation.
So far, I am just setting all the values of the members not contained in that list to null . But this solution is not optimal because eg members of type datetime are serialized to "0001-01-01T00:00:00" and in addition, the response contains a lot of unnecessary information (the responses can grow up to 150MB). So it would be nicer to simply remove the members from the serialization process.

Answer 1

You can use the attributes:

[XmlIgnore] for XML or [JsonIgnore] for JSON.

For example:

[XmlIgnore]
public string MyString { get; set; }

or

[JsonIgnore]
public string MyString { get; set; }

Hope this helps.

Answer 2

I worked around it with [DataMember(EmitDefaultValue = false)] . So all my properties which are set to null are not included in the response. However, this is not the best solution because now I can't send any null values and swagger also shows the full model.