c# - Change values in JSON file (writing files)

Question

I have a settings.json file present in the Release folder of my application. What I want to do is change the value of it, not temporarily, permanently.. That means, deleting the old entry, writing a new one and saving it.

Here is the format of the JSON file

{
"Admins":["234567"],
"ApiKey":"Text",
"mainLog": "syslog.log",
"UseSeparateProcesses": "false",
"AutoStartAllBots": "true",
"Bots": [
    {
        "Username":"BOT USERNAME",
        "Password":"BOT PASSWORD",
        "DisplayName":"TestBot",
        "Backpack":"",
        "ChatResponse":"Hi there bro",
        "logFile": "TestBot.log",
        "BotControlClass": "Text",
        "MaximumTradeTime":180,
        "MaximumActionGap":30,
        "DisplayNamePrefix":"[AutomatedBot] ",
        "TradePollingInterval":800,
        "LogLevel":"Success",
        "AutoStart": "true"
    }
]
}

Suppose I want to change the password value and instead of BOT PASSWORD I want it to be only password. How do I do that?

Answer 1

Here's a simple & cheap way to do it (assuming .NET 4.0 and up):

string json = File.ReadAllText("settings.json");
dynamic jsonObj = Newtonsoft.Json.JsonConvert.DeserializeObject(json);
jsonObj["Bots"][0]["Password"] = "new password";
string output = Newtonsoft.Json.JsonConvert.SerializeObject(jsonObj, Newtonsoft.Json.Formatting.Indented);
File.WriteAllText("settings.json", output);

The use of dynamic lets you index right into json objects and arrays very simply. However, you do lose out on compile-time checking. For quick-and-dirty it's really nice but for production code you'd probably want the fully fleshed-out classes as per @gitesh.tyagi's solution.