如何全屏支持添加到浏览器GeckoFx？

Question

我建立一个C＃.NET Windows窗体应用程序的Web浏览器，并希望增加对全屏使用（主要是对HTML5视频）的支持。

这样，当用户按下像YouTube视频的视频全屏按钮，视频将占据整个屏幕。

浏览器使用一个GeckoFx控制以查看interweb。我将如何去这样做呢？

Answer 1

设置浏览器控件Dock属性Dock.Fill。 你可以在那里当前显示你程序Screen大小，并使用其Bounds大小表单。

订阅Resize事件。当窗体最大化，删除边框（这将删除标题栏，太），设置FormWindowState回FormWindowState.Normal（否则你将无法使用全屏幕大小），然后根据需要调整它的大小。

你的应用程序应该是DPIAware（如果它没有看到here）。 你也应该处理F11键允许用户最大化/正常化窗体的窗口。

using System;
using System.Drawing;
using System.Windows.Forms;
using Gecko;
using Screen = System.Windows.Forms.Screen;

public partial class Form1 : Form
{
    bool IsMaximized = false;
    bool TheaterClicked = false;
    Rectangle previousPosition = Rectangle.Empty;
    string UserAgent = "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0";
    public Form1()
    {
        InitializeComponent();
        Xpcom.Initialize("Firefox");
        GeckoPreferences.User["full-screen-api.enabled"] = true;
        GeckoPreferences.Default["full-screen-api.enabled"] = true;
        GeckoPreferences.User["general.useragent.override"] = UserAgent;
        GeckoPreferences.Default["general.useragent.override"] = UserAgent;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        previousPosition = this.Bounds;
        this.geckoWebBrowser1.Navigate("[Some URL]");
        this.geckoWebBrowser1.GetDocShellAttribute().SetFullscreenAllowed(true);
    }

    private void Form1_Resize(object sender, EventArgs e)
    {
        if (this.WindowState == FormWindowState.Maximized) { 
            SetWindowState(this.WindowState, false);
        }
        else if (!this.IsMaximized) { 
            this.previousPosition = this.Bounds;
        }
    }

    private void geckoWebBrowser1_DomMouseDown(object sender, DomMouseEventArgs e)
    {
        if (geckoWebBrowser1.Url.Host.Contains("youtu"))
        {
            GeckoHtmlElement elm = (GeckoHtmlElement)e.Target.CastToGeckoElement();
            switch (elm.ClassName)
            {
                case "ytp-fullscreen-button ytp-button":
                    if (this.geckoWebBrowser1.Document.GetElementsByClassName("ytp-size-button ytp-button").FirstOrDefault() is GeckoHtmlElement theater)
                    {
                        if (this.TheaterClicked == false) {
                            theater.Click();
                            this.TheaterClicked = true;
                        }
                    }
                    break;
                case "ytp-size-button ytp-button":
                    this.TheaterClicked = !this.TheaterClicked;
                    break;
                default:
                    break;
            }
        }
    }

    private void SetWindowState(FormWindowState state, bool setSize)
    {
        if (state == FormWindowState.Maximized) {
            this.IsMaximized = true;
            if (setSize) this.previousPosition = this.Bounds;
            this.WindowState = FormWindowState.Normal;
            this.FormBorderStyle = FormBorderStyle.None;
            this.Location = Point.Empty;
            this.Size = Screen.FromHandle(this.Handle).Bounds.Size;
        }
        else {
            this.FormBorderStyle = FormBorderStyle.Sizable;
            this.Bounds = this.previousPosition;
            this.IsMaximized = false;
        }
    }

    protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
    {
        base.ProcessCmdKey(ref msg, keyData);
        if (keyData == Keys.F11) {
            SetWindowState(this.IsMaximized ? FormWindowState.Normal : FormWindowState.Maximized, true);
            return true;
        }
        else {
            return false;
        }
    }
}