BQuery

BQuery is a Blazor helper library for JavaScript interop (inspired by jQuery).

It provides:

• Element DOM helpers (Attr, class/style helpers)
• Element measurement and position APIs
• Viewport measurement APIs
• Window event binding with .NET callbacks
• Element drag helpers

Live demo

Target Frameworks

BQuery	.NET
4.x	.NET 8.0 / .NET 10.0
3.x	.NET 6
2.x	.NET 5

Breaking changes (4.0.0)

If you're upgrading from 3.x, please review the following API and platform changes:

• Target frameworks changed: BQuery 4.x targets .NET 8.0 and .NET 10.0 only. .NET 6 is no longer supported.
• Startup extensions removed: the old AspNetExtensions package surface (for example UseBQuery(...)) was removed. Use DI registration with AddBQuery() and load the static asset from _content/BQuery/dist/....
• Resize callback payload changed: resize handlers now use ResizeEventArgs (with named properties like width/height) instead of positional payload patterns.

Upgrade checklist

1. Update your app TFM to .NET 8+.
2. Replace legacy startup extension usage with builder.Services.AddBQuery();.
3. Ensure your host page (or startup script flow) loads _content/BQuery/dist/bQuery.min.js.
4. Update resize event handlers to OnResizeAsync(ResizeEventArgs args) / OnResize(ResizeEventArgs args).

Install

dotnet add package BQuery

Quick Start

1. Register services

builder.Services.AddBQuery();

Note

If using Interactive Auto render mode, the service needs to be registered in both the App and App.Client simultaneously.

2. Load the script

Add this script to your host page:

<script src="_content/BQuery/dist/bQuery.min.js"></script>

The repository samples use the UMD build (bQuery.min.js).

WASM example (wwwroot/index.html)

<script src="_content/BQuery/dist/bQuery.min.js"></script>
<script src="_framework/blazor.webassembly.js"></script>

Server example (Pages/_Host.cshtml)

<script src="_content/BQuery/dist/bQuery.min.js"></script>
<script src="_framework/blazor.server.js"></script>

Auto Mode (App.razor)

<script src="_content/BQuery/dist/bQuery.min.js"></script>
<script src="@Assets["_framework/blazor.web.js"]"></script>

3. Use Bq in components

@inject Bq bq
@implements IAsyncDisposable

@code {
    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (!firstRender)
        {
            return;
        }

        await bq.AddWindowEventListener<ResizeEventArgs>(WindowEvent.OnResize, OnResizeAsync);
    }

    private Task OnResizeAsync(ResizeEventArgs args)
    {
        Console.WriteLine($"Viewport: {args.Width} x {args.Height}");
        return Task.CompletedTask;
    }

    public async ValueTask DisposeAsync()
    {   
        // Remove only this component's callback. Other subscribers share the scope.
        await bq.RemoveWindowEventListener<ResizeEventArgs>(WindowEvent.OnResize, OnResizeAsync);
    }
}

Common Usage

Viewport

var width = await bq.Viewport.GetWidthAsync();
var height = await bq.Viewport.GetHeightAsync();
var scrollTop = await bq.Viewport.GetScrollTopAsync();

Element APIs (ElementReference extensions)

var size = await element.GetWidthAndHeightAsync();
var docPos = await element.GetPositionInDocAsync();

await element.AddCls("is-active");
await element.Css("display", "none");
await element.RemoveCls("is-active");

Drag

await bq.Drag.BindDragAsync(dialog, new DragOptions
{
    InViewport = true,
    DragElement = dialogHeader
});

await bq.Drag.ResetDragPositionAsync(dialog, new DragOptions
{
    DragElement = dialogHeader
});

await bq.Drag.RemoveDragAsync(dialog, new DragOptions
{
    DragElement = dialogHeader
});

User agent

var ua1 = await bq.GetUserAgentAsync();
var ua2 = await jsRuntime.GetUserAgentAsync(); // IJSRuntime extension

API Docs

• C# API: API.md
• TypeScript API: TS-API.md

Samples

• Sample/BQuery.Sample.Wasm
• Sample/BQuery.Sample.Server
• Sample/BQuery.Sample.Client — shared WebAssembly bootstrap for Wasm and Auto
• Sample/BQuery.Sample.Common
• Sample/BQuery.Sample.Auto

The three .NET 10 hosts share the same English interactive laboratory. Server (5301), Wasm (5302), and Auto (5303) use Interactive Server, WebAssembly, and Auto respectively. See Sample guide and coverage for startup commands, routes, lifecycle notes and verification.

License

MIT