private void ToJsonSample()
{
SampleModel arg1 = new SampleModel();
arg1.Id = 1;
arg1.Name = "hoge";
string result1 = arg1.ToJson();
Console.WriteLine(result1);
// => "{"Id":1,"Name":"hoge"}"
SampleModel arg2 = null;
string result2 = arg2.ToJson();
Console.WriteLine(result2);
// => ""
}