在CefSharp winform中加载iframe

在我的winform应用程序中，我在cefsharp浏览器中加载了一个网页 . 在网页中有一个加载另一个网页的iframe .

在Chrome中，iframe已加载 . 在应用程序中，iframe保持空白 .

我似乎无法找到解决方案 .

我添加了一个处理程序：

browser.RequestHandler = New checkFrame()

    Public Class checkFrame
    Implements IRequestHandler

    Public Sub OnPluginCrashed(browserControl As IWebBrowser, browser As IBrowser, pluginPath As String) Implements IRequestHandler.OnPluginCrashed
    End Sub

    Public Sub OnRenderProcessTerminated(browserControl As IWebBrowser, browser As IBrowser, status As CefTerminationStatus) Implements IRequestHandler.OnRenderProcessTerminated
    End Sub

    Public Sub OnRenderViewReady(browserControl As IWebBrowser, browser As IBrowser) Implements IRequestHandler.OnRenderViewReady
    End Sub

    Public Sub OnResourceLoadComplete(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, request As IRequest, response As IResponse, status As UrlRequestStatus, receivedContentLength As Long) Implements IRequestHandler.OnResourceLoadComplete
    End Sub

    Public Sub OnResourceRedirect(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, request As IRequest, response As IResponse, ByRef newUrl As String) Implements IRequestHandler.OnResourceRedirect
    End Sub

    Public Function GetAuthCredentials(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, isProxy As Boolean, host As String, port As Integer, realm As String, scheme As String, callback As IAuthCallback) As Boolean Implements IRequestHandler.GetAuthCredentials
        callback.Dispose()
        Return False
    End Function

    Public Function GetResourceResponseFilter(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, request As IRequest, response As IResponse) As IResponseFilter Implements IRequestHandler.GetResourceResponseFilter
        Return Nothing
    End Function

    Public Function OnBeforeBrowse(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, request As IRequest, isRedirect As Boolean) As Boolean Implements IRequestHandler.OnBeforeBrowse
        Return False
    End Function

    Public Function OnBeforeResourceLoad(browserControl As IWebBrowser, browser As IBrowser, frame As IFrame, request As IRequest, callback As IRequestCallback) As CefReturnValue Implements IRequestHandler.OnBeforeResourceLoad
        'Console.Write(request.Url + Environment.NewLine)
        Return CefReturnValue.Continue
    End Function


End Class

有没有人知道我需要更改或添加所以iframe被加载？

谢谢