Read json file c#

gistfile1.txt

public static void ReplaceJsonValue()
{
    string filepath = "../../json1.json";
    string result = string.Empty;
    using (StreamReader r = new StreamReader(filepath))
    {
        var json = r.ReadToEnd();
        var jobj = JObject.Parse(json);       
        foreach (var item in jobj.Properties()) {
            item.Value = item.Value.ToString().Replace("v1", "v2");                   
        }
        result = jobj.ToString();
        Console.WriteLine(result);              
    }
    File.WriteAllText(filepath, result);
}