string json = @" {""data"":[{""Name"":""Yaj"",""Number"":""null"",""Name"":""null"",""PhotoUrl"":""http://worldforme.com/rfr/fr"",""date"":""1994-06-14 00:00:00.000"",""ID"":""178"",""ssid"":""1"",""InOut"":""Incoming"",""Intime"":""null"",""OutTime"":""null"",""Por"":""null""}]}";
var dt = JsonConvert.DeserializeObject<mainlist>(json);
dtがnullを返します。JSON文字列を逆シリアル化する必要があります
あなたは 'mainlist'クラスを投稿できますか? – Asnivor