GTKWebkitWebView change WebDataDir and WebCacheDir

[badcel]

Discussed in #1471

^{Originally posted by andreasld97 March 12, 2026}
Hi,

I am just using a normal WebView trying to change the folders where it stores its content (because I will use multiple webviews in my project). The documentation (https://webkitgtk.org/reference/webkitgtk/stable/migrating-to-webkitgtk-6.0.html#network-session-api) here says the following:

"[...] WebKitNetworkSession to be used must be passed to the WebKitWebView as a construct parameter."

So thats what I am trying, but I dont know how to do this right. I managed to create a new NetworkSession with the pathes which is simple, but is it even possible to pass it using the ConstructArgument from the bindings?

Heres my code:

using GObject;
using WebKit;

internal class Program
{
    private static void Main(string[] args)
    {
        WebKit.Module.Initialize();

        var _app = Adw.Application.New("Test.App", Gio.ApplicationFlags.FlagsNone);
        _app.OnActivate += (sender, args) =>
        {
            var _window = Gtk.ApplicationWindow.New(_app);
            _window.Title = $"Test";
            _window.SetDefaultSize(800, 600);

            var webView = CreateWebView("/home/andy/test/data", "/home/andy/test/cache"); // new WebView();
            webView.LoadUri("https://www.google.de");

            _window.SetChild(webView);
            _window.Show();
        };

        _app.OnShutdown += (sender, args) => { };

        _app.Run([]);

        WebView CreateWebView(string webDataDir, string webCacheDir)
        {
            try
            {
                // "[...] WebKitNetworkSession to be used must be passed to the WebKitWebView as a construct parameter." (https://webkitgtk.org/reference/webkitgtk/stable/migrating-to-webkitgtk-6.0.html#network-session-api)
                var networkSession = NetworkSession.New(webDataDir, webCacheDir);

                // Problem: The specified structure must be blittable or have layout information. (Parameter 'structure'):
                return new WebView(new ConstructArgument("network-session", new Value(networkSession)));
            }
            catch (Exception ex)
            {
                return null;
            }
        }
    }
}

So here I get the exception that the specified structure must be blittable or have layout information. May I only pass primitive types here? But the property is a construct-only-property as you can see here: https://webkitgtk.org/reference/webkitgtk/stable/property.WebView.network-session.html. So it seems like there is the only way to pass it via constructor?