如何重新加载WKWebView?

WKWebView 但内容没有出现,旧的内容仍然存在。知道为什么吗?

WKWebViewConfiguration *c = [WKWebViewConfiguration new];
pdfView = [[WKWebView alloc] initWithFrame:CGRectZero configuration:c];
pdfView.UIDelegate = self;
pdfView.navigationDelegate = self;
pdfView.scrollView.delegate = self;
[cell.contentView addSubview:pdfView];
[pdfView loadFileURL:[NSURL fileURLWithPath:filePath] allowingReadAccessToURL:[NSURL fileURLWithPath:filePath]];
[pdfView loadFileURL:[NSURL fileURLWithPath:filePathNEW] allowingReadAccessToURL:[NSURL fileURLWithPath:filePathNEW]];

reload() 不起作用。只是重新创造了整个 WKWebView网站