Data

JSON values edited as a tree, from the optional Joufflu.Data package.

  • Data fill — fills in a value against a JSON Schema.
  • Data edit — builds a value from scratch.
  • Data display — shows a value read only.

Add the package (dotnet add package Joufflu.Data). Only the core Resources.xaml needs merging. The snippets use:

xmlns:data="clr-namespace:Joufflu.Data.Controls;assembly=Joufflu.Data"

using Joufflu.Data.Model;
using NJsonSchema;
using DataObject = Joufflu.Data.Model.DataObject; // System.Windows has one too

Nodes

The controls take a Node: DataFill and DataEdit edit a DataObject root in place, DataDisplay only shows it, and takes any node or a JToken (Data display).

Node Holds
DataObject Properties, keyed by unique, case-sensitive keys
DataArray Values, keyed [0], [1]…, and the Template new items are cloned from
DataValue a Value, or the Options of an enum

ToToken() returns the JSON:

string? json = Node.ToToken()?.ToString();

From a schema

ToDataNode() builds the tree of an NJsonSchema JsonSchema:

Node = (DataObject)JsonSchema.FromType<Order>().ToDataNode();
Schema Editor Written as
string TextBox string
string, format date / date-time DatePicker ISO 8601 string
string, format time-span / duration TimeSpanPicker [d.]hh:mm:ss string
integer NumericUpDown number
number DecimalUpDown number
boolean CheckBox true / false
enum ComboBox, named by x-enumNames the option’s value
array / object tree array / object

New values start at null when nullable, else at the type’s default ("", 0, false, today, the first option).

Not supported: arrays with a list of item schemas, or with no items schema. A schema with no type ({}) becomes a value filled in as free text.

To a schema

ToJsonSchema() does the reverse: the schema of a tree, built from a schema or with DataEdit, following the table above (time spans get the time-span format):

JsonSchema schema = Node.ToJsonSchema();
string json = schema.ToJson();

Keys, Description, IsNullable, IsRequired and the enum Options are kept; values are not.

From JSON

Load() fills a tree with a JSON value, the reverse of ToToken(), to edit a value again:

Node = (DataObject)schema.ToDataNode();
Node.Load(JToken.Parse(json), ManualValues);

The tree keeps its shape. A node matching one of the manual values, or one its editor can’t hold (an object given a string, say), is forced to it rather than lost; a property the JSON leaves out is forced to undefined when not required.

Without a schema, ToDataNode() on a JToken infers the tree from the value, for DataEdit:

Node = (DataObject)JObject.Parse(json).ToDataNode();

ReadDataNode() gives the same tree straight from a JsonReader, for a large file: it is never held as tokens too (open a file). A key given twice keeps its last value, comments are skipped.

using var reader = new JsonTextReader(File.OpenText(path));
DataNode node = reader.ReadDataNode();

Changed is raised when the data of a node or of anything under it changes, to react to an edit anywhere in the tree: a key, a value, the manual mode or entry, an array template, children added or removed. Expanding a node, flagging a duplicate key or moving a node to another parent change no data and raise nothing.

Manual values

ManualValues lists what a field can be forced to instead of its editor, like a placeholder resolved later. Each entry names the type it fits (null fits any):

public IReadOnlyList<DataManualValue> ManualValues { get; } =
[
    new(EnumDataType.String, "TBD"),
    new(EnumDataType.Integer, -1L),
];

The feather toggle swaps a field’s editor for the entries that fit it, plus undefined (the property is left out) when not required and null when nullable. It is disabled when nothing fits. Objects and arrays have it too: forced, their properties or items are hidden and the entry is written in their place, and they come back as they were once released.

An entry that takes any name is a DataManualPattern, the name written between braces:

new DataManualPattern(null, "$row.columns['{column name}']"),

The list shows it as the hint $row.columns['column name'], which can’t be picked. Typing unit price offers $row.columns['unit price'] in its place. Load forces a value the pattern writes back to it.

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