DKNet

Fill a template from objects or dictionaries

Part of DKNet.Svc.Transformation. Transform/TransformAsync extract every token in the template, resolve each one against the parameters you pass, and rebuild the string in a single pass.

var order = new { OrderId = 4711, Total = 129.5m, Placed = new DateTime(2026, 3, 1), Paid = true };
var text = transformer.Transform("Order [OrderId] — [Total] on [Placed]. Paid: [Paid]", order);
// Order 4,711 — 129.50 on 01/03/2026 12.00.00. Paid: Yes

Resolution walks the parameters array in order, then falls back to TransformOptions.GlobalParameters (set at registration). For each entry: an IDictionary<string, string> passed directly as a Transform/TransformAsync argument is looked up by key, case-insensitively; an IEnumerable<object> — including GlobalParameters itself — is searched recursively, item by item, and its items resolve by property only, so a dictionary inside a collection or in GlobalParameters is not looked up by key; anything else is treated as an object — a public instance property matching the token name wins, and a non-public one is tried next. The first non-null value wins.

Each parameter is tried through TokenResolver.Resolve, which picks the lookup — dictionary key, collection search, or property reflection — from the object's runtime type; the first non-null value found wins.

This does not show the not-found policy (below) or value formatting, which run after resolution for every token regardless of which source supplied the value.

public enum TokenNotFoundBehavior { LeaveAsIs, Remove, ThrowError } // default: ThrowError

ThrowError (the default) throws UnResolvedTokenException on the first token nothing can resolve. LeaveAsIs keeps the token text verbatim. Remove replaces it with an empty string. A property that exists but holds null counts as unresolved — there is no way to distinguish “missing” from “null” here.

⚙️ Configuration reference

Option	Type	Default	Effect
`TokenNotFoundBehavior`	`TokenNotFoundBehavior`	`ThrowError`	`LeaveAsIs` / `Remove` for lenient rendering instead of throwing `UnResolvedTokenException`.
`GlobalParameters`	`IEnumerable<object>`	`[]`	Fallback resolution sources tried after the call’s own `parameters`. Configured at registration.

⚠️ Gotchas & limits

A dictionary parameter must be IDictionary<string, string>. Any other IDictionary throws ArgumentException during resolution — including Dictionary<string, object>.
No nested-property or dotted paths. [Customer.Name] is looked up as a single property literally named Customer.Name, which normally fails; flatten your data (project to an anonymous object or dictionary) first.
Non-public properties are readable. Resolution falls back to non-public instance properties, so a token can pull a value the type does not expose publicly. Don’t pass entities with sensitive internal state into a user-authored template.
Resolved values are cached only for the current call. The cache key is the token string, scoped to a single Transform/TransformAsync call — a token repeated twice in the same template resolves once, but nothing is ever shared across calls or across a reused ITransformerService instance.

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