如何使用WebView2下载文件到内存？

Question

我想将WebView2中的文件下载到内存中，而不是保存到磁盘上。 但是，我在 WebView2 中找不到允许我执行任何操作的方法，除了更改文件在磁盘上存储的路径，即。

formWebView2.webView2.CoreWebView2.Profile.DefaultDownloadFolderPath = filePath;

这可以将其保存到磁盘

TaskCompletionSource<bool> downloadTaskCompletionSource = new TaskCompletionSource<bool>();
formWebView2.webView2.CoreWebView2.DownloadStarting += delegate (object sender, CoreWebView2DownloadStartingEventArgs args) {
    args.DownloadOperation.StateChanged += delegate (object sender, Object e) {
    switch (args.DownloadOperation.State) {
        case CoreWebView2DownloadState.Completed:
            downloadTaskCompletionSource.TrySetResult(true); // Continue when the download is completed
            break;
        }
    };
};

// Click on the DOWNLOAD button
string script = @"(function(){
    var status = 'ERROR';
    const downloadDataButtons = document.getElementsByClassName('historical-data__controls-button--download historical-download');
    if (downloadDataButtons.length == 1) { // Check to make sure there is only one such button
        downloadDataButtons[0].click();
        status = 'OK';
    }
    return status;
})();";
string javaScriptResponse = await formWebView2.webView2.ExecuteScriptAsync(script);

await downloadTaskCompletionSource.Task; // Wait for the file to finish downloading

使用WebClient，您可以使用MemoryStream和StreamReader将文件保存到内存并从内存中读取它

using (MemoryStream memoryStream = new MemoryStream(webClient.DownloadData(url))) {
    memoryStream.Position = 0; // Start the memoryStream at the beginning
    using (StreamReader streamReader = new StreamReader(memoryStream)) {
        for (int lineNumber = 0; lineNumber < memoryStream.Length; lineNumber++) {
            String line = streamReader.ReadLine();
        }
    }
}

WebView2中有没有办法将其下载到MemoryStream而不是磁盘？ 我可以添加 RAM 磁盘，但除其他缺点外，我必须分配大量额外的 RAM，以防用户下载大文件。

Answer 1

如果我正确理解你的问题，它与WebView2无关。
我使用这个（代码改编自 EssentialsObjects）：
你需要你想要下载的文件的 url，然后你会得到一个字节数组；请自行决定使用它。

public static byte[] getDataFromUrl(string url)
        {
            System.Net.WebClient wc = new System.Net.WebClient();
            wc.OpenRead(url);
            int bytes_total = Convert.ToInt32(wc.ResponseHeaders["Content-Length"]);
            System.Net.HttpWebRequest request = null;
            System.Net.HttpWebResponse response = null;
            byte[] b = null;
            request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
            try
            {
                response = (System.Net.HttpWebResponse)request.GetResponse();
            }
            catch (Exception ex)
            {
                //error message here
                return null;
            }
            if (request.HaveResponse)
            {
                if (response.StatusCode == System.Net.HttpStatusCode.OK)
                {
                    Stream receiveStream = response.GetResponseStream();
                    using (BinaryReader br = new BinaryReader(receiveStream))
                    {
                        b = br.ReadBytes(bytes_total + 1000);
                        br.Close();
                    }
                }
            }
            return b;
        }