Playwright

Playwright usually manages its own browser builds. It also supports connecting to a running Chromium over the Chrome DevTools Protocol, or CDP, which is how it attaches to DotNetBrowser.

Read DevTools Protocol first for the rules that apply to every automation tool.

Prerequisites 

Reference the Microsoft.Playwright NuGet package in the project that runs the scenario.

Because Playwright attaches to a browser that already exists, you do not need to run playwright install. Its Node-based driver is still required, but the NuGet package deploys that with the application.

Enabling the endpoint 

Create the engine with RemoteDebuggingPort set to a free port, as described in DevTools Protocol. The example uses 9223.

Connecting Playwright 

Create a Playwright instance and connect it to the endpoint:

using IPlaywright playwright = await Microsoft.Playwright.Playwright.CreateAsync();

// Connect to the browser using CDP
Microsoft.Playwright.IBrowser playwrightBrowser =
    await playwright.Chromium
                    .ConnectOverCDPAsync($"http://localhost:{RemoteDebuggingPort}");

IBrowserContext browserContext = playwrightBrowser.Contexts[0];
await browserContext.GrantPermissionsAsync(new[] { "geolocation" });
await browserContext.SetGeolocationAsync(new Geolocation
{
    Latitude = 42.746635f,
    Longitude = -75.770045f
});

IPage page = browserContext.Pages[0];
await page.GotoAsync(LocationUrl);
await page.WaitForSelectorAsync("title");

// Scroll the map into view
await page.Locator("#map").ScrollIntoViewIfNeededAsync();

Using _
    playwright As IPlaywright =
        Await Microsoft.Playwright.Playwright.CreateAsync()
    ' Connect to the browser using CDP
    Dim playwrightBrowser As IBrowser =
            Await _
            playwright.Chromium.ConnectOverCDPAsync(
                $"http://localhost:{RemoteDebuggingPort}")

    Dim browserContext As IBrowserContext = playwrightBrowser.Contexts(0)
    Await browserContext.GrantPermissionsAsync({"geolocation"})
    Await browserContext.SetGeolocationAsync(New Geolocation With {
                                                .Latitude = 42.746635F,
                                                .Longitude = - 75.770045F
                                                })

    Dim page As IPage = browserContext.Pages(0)
    Await page.GotoAsync(LocationUrl)
    Await page.WaitForSelectorAsync("title")

    ' Scroll the map into view
    Await page.Locator("#map").ScrollIntoViewIfNeededAsync()
End Using

ConnectOverCDPAsync takes the endpoint URL, http://localhost:9223 here, and returns a browser object backed by the running engine.

The example then takes Contexts[0] and Pages[0] rather than creating a context or a page. Those are the context and the page your application already displays, so everything the scenario does is visible in the BrowserView control.

What CDP mode covers 

The Playwright documentation describes a CDP connection as lower fidelity than Playwright’s own protocol. Page-level automation works as usual, with two limits:

• Playwright normally launches Chromium with a fixed set of command-line switches and expects them to be in effect. DotNetBrowser starts Chromium with a different set, so a Playwright feature that relies on one of those switches can behave differently here. The Playwright documentation covers this.
• Anything that assumes Playwright owns the browser process — closing the browser, launch options, and the tooling built on them — does not apply.

Threading and lifetime 

The example connects after the first Navigation.LoadUrl call completes, so the engine is running by the time Playwright attaches. Playwright calls are asynchronous and run off the UI thread; marshal results back before touching controls.

The IBrowser name collision 

Both libraries define an IBrowser interface. In C#, the example resolves this with an alias:

using IBrowser = DotNetBrowser.Browser.IBrowser;

Microsoft.Playwright.IBrowser is then written out in full where it is needed. The VB.NET example qualifies the DotNetBrowser type instead, as DotNetBrowser.Browser.IBrowser.

The complete example is available in our repository: C#, VB.NET.