如何在 Maui Blazor 使用 BlazorWebView 像本机浏览器一样下载文件？

总结: Windows 和 Android 可以实现, ios/mac 使用的是 WKWebView , 研究了一部分，感兴趣的大佬接棒吧.

关键代码

MainPage.xaml.cs

#if ANDROID
using Android.Webkit;
using AndroidX.Activity;
#elif WINDOWS
using Microsoft.Web.WebView2.Core;
#endif

protected string UploadPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "uploads");

public MainPage()
{
    InitializeComponent();
    blazorWebView.BlazorWebViewInitialized += BlazorWebViewInitialized;
}

private void BlazorWebViewInitialized(object? sender, BlazorWebViewInitializedEventArgs e)
{
      #if ANDROID
      if (e.WebView.Context?.GetActivity() is not ComponentActivity activity)
      {
          e.WebView.Download +=(async (s,e)=> await WebView_DownloadAsync(s,e));
      }
      #elif WINDOWS
      e.WebView.CoreWebView2.DownloadStarting += (async (s, e) => await CoreWebView2_DownloadStartingAsync(s, e)); 
      #endif
}

#if WINDOWS
private async Task CoreWebView2_DownloadStartingAsync(object sender, CoreWebView2DownloadStartingEventArgs e)
{
      var downloadOperation = e.DownloadOperation;
      string fileName = Path.GetFileName(e.ResultFilePath);
      var filePath = Path.Combine(UploadPath, fileName);
      e.ResultFilePath = filePath;
      await DisplayAlert("提示", $"下载文件完成 {fileName}", "OK");
}
#endif


#if ANDROID
private async Task WebView_DownloadAsync(object sender, DownloadEventArgs e)
{
      Uri uri = new Uri(e.Url);
      string fileName = Path.GetFileName(uri.LocalPath);
      var httpClient = new HttpClient();
      var filePath = Path.Combine(UploadPath, fileName);
      byte[] fileBytes = await httpClient.GetByteArrayAsync(e.Url);
      File.WriteAllBytes(filePath, fileBytes);
      await DisplayAlert("提示", $"下载文件完成 {fileName}", "OK");
}
#endif

ios/mac的思路，拦截这里

MainPage.xaml.cs

        public MainPage()
        {
            InitializeComponent();

            blazorWebView.BlazorWebViewInitialized += BlazorWebViewInitialized;
            blazorWebView.BlazorWebViewInitializing += BlazorWebViewInitializing;

            blazorWebView.UrlLoading +=
            (sender, urlLoadingEventArgs) =>
            {
                if (urlLoadingEventArgs.Url.Host != "0.0.0.0")
                {
                    //外部链接WebView内打开,例如pdf浏览器
                    Console.WriteLine(urlLoadingEventArgs.Url);
                    urlLoadingEventArgs.UrlLoadingStrategy =
                        UrlLoadingStrategy.OpenInWebView;

                    //拦截可处理 IOS || MACCATALYST 下载文件, 简单测试一下
                    if (urlLoadingEventArgs.Url.ToString().EndsWith(".exe"))
                    {
                        Task.Run(async () => await DownloadAsync(urlLoadingEventArgs.Url.ToString()));
                    }
                }
            };
        }