Table of Contents

Dynamic Settings Bag

SettingsBag internally stores a key/value dictionary. Any type of value can be passed as long as Json.NET knows how to serialize it. SettingsBag has a built-in feature for autosaving that can be enabled by calling EnableAutosave() without WPF binding support.

It is a sealed class in the Nucs.JsonSettings namespace, so there is no class to define — just load it and go.

Basic usage

using Nucs.JsonSettings;

var settings = JsonSettings.Load<SettingsBag>("config.json"); //created if it doesn't exist

settings["somekey"]        = "with some value";
settings["someotherkey"]   = 1;
settings["somekeyforclass"] = new SmallClass { Name = "Small", Value = "Class" };
settings.Save();

//validate — reload from disk
settings = JsonSettings.Load<SettingsBag>("config.json");
Console.WriteLine(settings["somekey"]);      // with some value
Console.WriteLine(settings["someotherkey"]); // 1

Nullable value-type semantics

Value types come back as Nullable<T>, so a missing key returns null rather than throwing or returning a default:

dynamic dyn = settings.AsDynamic();
if ((int?)dyn.someotherkey == 1)
    Console.WriteLine("matched");

var missing = (int?)dyn.doesNotExist; // null, not 0

Typed retrieval with Get<T>

Get<T>(key, @default) reads a value and converts it to T. Because Json.NET deserializes a JSON integer back as long, a value stored as int is a boxed long once reloaded; Get<int> bridges that width through Convert.ChangeType instead of throwing. A missing key — or a stored null — returns the @default you pass (or default(T)):

settings["count"] = 3;
settings.Save();
settings = JsonSettings.Load<SettingsBag>("config.json");

int count   = settings.Get<int>("count");      // 3, even though it reloaded as Int64
int retries = settings.Get<int>("retries", 5); // 5 — key absent, so the default is used

The dynamic view

AsDynamic() returns a dynamic wrapper (DynamicSettingsBag) so you can use member syntax instead of the indexer:

dynamic dyn = settings.AsDynamic();
dyn.key = "dat value tho";  // same as settings["key"] = "dat value tho";
dyn.Save();                 // same as settings.Save();

Autosave

SettingsBag has its own dictionary-backed autosave implementation (separate from the [Autosave] weaving hardcoded classes use), so a plain EnableAutosave() is enough:

var settings = JsonSettings.Load<SettingsBag>("config.json").EnableAutosave();

settings["somekey"] = "with some value"; //Saved!
settings.AsDynamic().another = 42;        //Saved!

See Autosave for suspension and the hardcoded-class story.

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