3.9 KiB
ToastViewport
The fixed container where toast notifications appear. Place exactly one ToastViewport in your main layout — it sits in the corner of the screen and is invisible when no toasts are showing. New toasts stack upward as they are added.
Quick example
<!-- MainLayout.htmx -->
<body>
<main>$$Body$$</main>
$$ToastViewport$$
</body>
// MainLayout.htmx.cs
_toastViewport = new ToastViewport();
That's all. Every call to window.showToast(...) will now display in the bottom-right corner of the screen.
All the options
public ToastViewport(string id = "toast-viewport")
| Parameter | What it does |
|---|---|
id |
The element id. components.js looks for #toast-viewport by default. Only change this if you also update the JavaScript. |
How it works
ToastViewport renders a single fixed <div> anchored to the bottom-right of the screen. It has pointer-events: none so it doesn't block clicks on the page behind it. Individual toasts set pointer-events: auto so their dismiss buttons are still clickable.
Toasts are appended to this element by window.showToast() and removed after their duration expires.
}
---
## Tips and tricks
- Place `ToastViewport` once in the outermost layout — not inside HTMX swap targets, since HTMX replaces the target's contents and would remove the viewport.
- The default id `"toast-viewport"` is hard-coded in `components.js` for the `showToast` lookup. If you rename it, update the JS too.
- `ToastViewport` renders as an empty `div` — it has no visual presence until a toast is appended to it.
- Multiple viewports on the same page are valid for different toast regions (e.g. top-right and bottom-right), but `showToast` will target whichever viewport id it is configured for.
- Multiple viewports on the same page are valid for different toast regions (e.g. top-right and bottom-right), but `showToast` will target whichever viewport id it is configured for.
---
## Complete page example
`ToastViewport` is a layout-level concern — it lives in `MainLayout`, not in individual page templates. The example below shows the full integration pattern.
**`Templates/MainLayout.htmx`** (excerpt)
```html
<body class="min-h-screen bg-background text-foreground">
$$NavBar$$
<main class="container mx-auto px-4 py-8">
$$Content$$
</main>
$$ToastViewport$$
$$Scripts$$
</body>
Templates/MainLayout.htmx.cs (excerpt)
namespace Htmx.ApiDemo.Templates;
public sealed class MainLayout : MainLayoutBase
{
private readonly IHtmxComponent _nav;
private readonly IHtmxComponent _content;
private readonly IHtmxComponent _viewport;
public MainLayout(IHtmxComponent content, IHtmxComponent nav)
{
_nav = nav;
_content = content;
// Place one viewport at bottom-right for all pages
_viewport = new Components.ToastViewport(
id: "toast-viewport",
position: "bottom-right");
}
protected override void RenderNavBar(HtmxRenderContext ctx) => _nav.Render(ctx.Next());
protected override void RenderContent(HtmxRenderContext ctx) => _content.Render(ctx.Next());
protected override void RenderToastViewport(HtmxRenderContext ctx) => _viewport.Render(ctx.Next());
}
Triggering a toast from any handler
// Any POST handler can fire a toast without changing the ToastViewport markup.
ctx.Response.Headers["HX-Trigger"] =
"""{"showToast":{"title":"Saved!","description":"Your changes have been persisted."}}""";
Two-viewport layout (top-right errors + bottom-right successes)
_errorViewport = new Components.ToastViewport(id: "error-viewport", position: "top-right");
_successViewport = new Components.ToastViewport(id: "success-viewport", position: "bottom-right");
// Error toast
ctx.Response.Headers["HX-Trigger"] =
"""{"showToast":{"viewportId":"error-viewport","title":"Something went wrong."}}""";