Conditional Widgets ​

Widgets and their elements can be shown, hidden, enabled, or disabled based on another setting — for example, hiding advanced options until a related toggle is turned on. Conditions are expressed the same way widget values are: pass a C# expression, and FludeX keeps it in sync automatically.

Widget-Level: Show or Hide a Whole Section ​

Call VisibleWhen / EnabledWhen on the builder when composing a widget:

csharp
Widget.Create()
    .WithTitle("ADVANCED")
    .WithDescription("Only shown once the feature is turned on.")
    .WithToggle("Verbose Logging", () => settings.VerboseLogging)
    .VisibleWhen(() => settings.AdvancedModeEnabled)
    .Build();

VisibleWhen controls whether the whole card is shown at all; EnabledWhen keeps the card visible but grays it out and blocks interaction. Both are also available directly on Widget.Descriptor, for widgets you built earlier and want to attach a condition to afterward.

Element-Level: Show or Hide a Single Control ​

Most With* element methods accept the same two optional parameters directly:

csharp
Widget.Create()
    .WithTitle("HAPTICS")
    .WithToggle("Enabled", () => haptics.Enabled)
    .WithToggle("Core", () => haptics.Core, visibleWhen: () => haptics.Enabled)
    .WithToggle("Widgets", () => haptics.Widgets, visibleWhen: () => haptics.Enabled)
    .Build();

This is the exact pattern FludeX's own Core Settings page uses — the Core and Widgets haptics toggles only appear once the master Enabled toggle is on.

For element constructors that can't take visibleWhen / enabledWhen directly (for example, ones with a trailing params array), call VisibleWhen(...) / EnabledWhen(...) on the returned element descriptor instead.

How Conditions Are Evaluated ​

  • Conditions are live bindings, not one-time checks — the same expression-based binding used for widget values (see Data Binding). Change the backing property and the widget's visibility/enabled state updates immediately, with no manual refresh.
  • A missing or null condition, or one that throws, fails open — the widget stays visible and enabled rather than silently disappearing. A broken condition should never be the reason a control vanishes.
  • VisibleWhen removes the widget from layout entirely (no leftover gap), and the card's height animates smoothly to its new size as elements appear or disappear. EnabledWhen keeps the widget visible but non-interactive and visually dimmed.

Where It Applies ​

Both VisibleWhen and EnabledWhen work at two levels:

  • Widget — a whole titled card, via Widget.Create()...VisibleWhen()/.EnabledWhen(), or Widget.Descriptor.VisibleWhen()/.EnabledWhen() after construction
  • Element — a single control inside a widget, via the visibleWhen / enabledWhen parameters on its With* builder method, or ElementDescriptor.VisibleWhen()/.EnabledWhen()