Newtonsoft.JSON Deserialize the datetime string in c#?

Question

I have to deserialize a JSON string in C#. And in my serealize JSON string there is a datetime field. Below is the JSON string format -

{"Date" : "2016-09-20T18:29:00.0000000"}

But when I am desealizing the above string like below -

Newtonsoft.Json.JsonConvert.DeserializeObject<T>(entity, new IsoDateTimeConverter {
            DateTimeFormat = "yyyy-MM-dd'T'HH:mm:ss.fffffff"                
        });

I am getting the below string-

{"Date" : "2016-09-20T18:29:00"}

Means I am not getting the milliseconds value while it's 000.

Can anyone help me out on this.

Updating my question :

Actually I am deserializing my object/entity by Newtonsoft and which there is a datetime field which I want to format.

 return Newtonsoft.Json.JsonConvert.DeserializeObject<T>(entity, new IsoDateTimeConverter
        {
            DateTimeFormat = "yyyy-MM-dd'T'HH:mm:ss.fffffff"                             
        });

But as a result I am not getting the datetime format that I mentioned. It's truncating the datetime string from milliseconds. Below is my datetime string -

2016-09-20T18:29:00.000

And I am getting string like below after deserialzation -

2016-09-20T18:29:00