CefSharp 中的可拖动无边框 window

Question

我想在某些 HTML 元素上使用拖动逻辑实现无边框 window。我找到了一些工作示例（比如 frameless window for Chrome），这是我尝试过的：

.title-area 
{
   -webkit-app-region: drag;
}

<div class='title-area'>
    A draggable area
</div>

然后，在 C# 代码中我实现了 IDragHandler class:

internal class PromtDragHandler : IDragHandler
{
    bool IDragHandler.OnDragEnter(IWebBrowser browserControl, IBrowser browser, IDragData dragData, DragOperationsMask mask)
    {
        return false;
    }

    void IDragHandler.OnDraggableRegionsChanged(IWebBrowser browserControl, IBrowser browser, IList<DraggableRegion> regions)
    {

    }
}

方法 OnDraggableRegionsChanged 在开始时触发一次，OnDragEnter 在我拖动元素的某些文本时触发 "title-area"。但我不确定下一步该怎么做才能让我的 window 移动？

更新。 如评论中所述，CefTestApp 支持此拖动功能。在源代码中，我们有从 DragHandler 调用的方法 OnSetDraggableRegions:

void RootWindowWin::OnSetDraggableRegions(
const std::vector<CefDraggableRegion>& regions) {
REQUIRE_MAIN_THREAD();

// Reset draggable region.
  ::SetRectRgn(draggable_region_, 0, 0, 0, 0);

  // Determine new draggable region.
  std::vector<CefDraggableRegion>::const_iterator it = regions.begin();
  for (;it != regions.end(); ++it) {
    HRGN region = ::CreateRectRgn(
        it->bounds.x, it->bounds.y,
        it->bounds.x + it->bounds.width,
        it->bounds.y + it->bounds.height);
    ::CombineRgn(
        draggable_region_, draggable_region_, region,
        it->draggable ? RGN_OR : RGN_DIFF);
    ::DeleteObject(region);
  }

  // Subclass child window procedures in order to do hit-testing.
  // This will be a no-op, if it is already subclassed.
  if (hwnd_) {
    WNDENUMPROC proc = !regions.empty() ?
        SubclassWindowsProc : UnSubclassWindowsProc;
    ::EnumChildWindows(
        hwnd_, proc, reinterpret_cast<LPARAM>(draggable_region_));
  }
}

我还是不太明白，关于可拖动区域（开始时只触发一次）的信息究竟如何帮助移动window？有人可以向我解释这个逻辑或提供此代码的 C# 等效项吗？

Answer 1

更新2。我做到了。 这是我添加到表单代码中的内容：

IntPtr DragableRegionNative = Native.CreateRectRgn(0, 0, 0, 0);

    void RegionsChangedCallback(DraggableRegion[] Regions)
    {

        Native.SetRectRgn(DragableRegionNative, 0, 0, 0, 0);

        if (Regions == null)
            return;

        foreach (var Region in Regions)
        {
            var RegionNative = Native.CreateRectRgn(
                Region.X, Region.Y,
                Region.X + Region.Width,
                Region.Y + Region.Height);

            Native.CombineRgn(DragableRegionNative, DragableRegionNative, RegionNative,
                Region.Draggable ? (int)Native.CombineRgnStyles.RGN_OR : (int)Native.CombineRgnStyles.RGN_DIFF);

            Native.DeleteObject(RegionNative);
        }
    }


    Point dragOffset = new Point();

    protected override void OnMouseDown(MouseEventArgs e)
    {
        base.OnMouseDown(e);

        if (e.Button == MouseButtons.Left)
        {
            dragOffset = this.PointToScreen(e.Location);
            dragOffset.X -= Location.X;
            dragOffset.Y -= Location.Y;
        }
    }

    protected override void OnMouseMove(MouseEventArgs e)
    {
        base.OnMouseMove(e);

        if (e.Button == MouseButtons.Left)
        {
            Point newLocation = this.PointToScreen(e.Location);

            newLocation.X -= dragOffset.X;
            newLocation.Y -= dragOffset.Y;

            Location = newLocation;
        }
    }

    void chromewb_IsBrowserInitializedChanged(object sender, IsBrowserInitializedChangedEventArgs e)
    {
        if (chromewb.IsBrowserInitialized)
        {
            ChromeWidgetMessageInterceptor.SetupLoop(chromewb, (m) =>
            {
                if (m.Msg == (int)Native.WM.WM_LBUTTONDOWN)
                {
                    var point = Native.ParsePoint(m.LParam.ToInt32());

                    if (Native.PtInRegion(DragableRegionNative, point.X, point.Y))
                        this.InvokeEx(() => Native.PostMessage(this.Handle, (uint)m.Msg, m.WParam, m.LParam));

                }
            });
        }
    }

如你所见，从chrome浏览器拦截WM_LBUTTONDOWN事件就足够了，然后检查鼠标点是否属于标题区域，如果是，则将此消息发送到主窗体.一旦表单获得 WM_LBUTTONDOWN 事件，build-in 表单方法 OnMouseDown 和 OnMouseMove 就会完成其他工作。

Answer 2

看看：https://github.com/qwqcode/CefSharpDraggableRegion

您可以在 CSS 中指定 -webkit-app-region: drag 来告诉 CefSharp 哪些区域是可拖动的（就像 OS 的标准标题栏）。

CefSharp 中的可拖动无边框 window

Draggable borderless window in CefSharp

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cefsharp