How to deserialize a Json string in c# - json

Question

I have this Json string in memory, and trying to deserialize into a class :
{
{ "Member_ColName": "Entity Name" , "Member_Key": "entityName" },
{ "Margin_ColName": "Margin", "Margin_Key": "Margin" },
{ "LookBack_ColName": "Lookback Interval (Days)", "LookBack_Key":"LookbackInterval"},
{ "ConfInterval": "Confidence Interval"," ConfInterval_Key": "ConfidenceInterval"}
}
My public class is defined as :
public class JsonParameters
{
string Member_ColName { get; set; }
string Member_Key { get; set; }
string Margin_ColName { get; set; }
string Margin_Key { get; set; }
string LookBack_ColName { get; set; }
string LookBack_Key { get; set; }
string ConfInterval { get; set; }
string ConfInterval_Key { get; set; }
}
My c# method is as follows:
public string getJsonParameters()
{
// file stream code omitted
JavaScriptSerializer ser = new JavaScriptSerializer();
string jsonStr = utf.GetString(buffer);
Classes.JsonParameters jsonData = (Classes.JsonParameters)ser.Deserialize(jsonStr, typeof(Classes.JsonParameters));
return jsonStr;
}
I've done this kind of thing before when reading in a string of dates, but I did something slightly different.
In this case I can't seem to deserialize the Json object.
Any advice would be appreciated.
thanks.
Bob