我有一个窗口,它使用了一些异步方法。然而,这只是挂UI(在这些行动)只有当我创建它在运行时,像这样:异步方法挂起UI
private void button_Click(object sender, RibbonControlEventArgs e)
{
AboutWindow SettingsWindow = new AboutWindow();
SettingsWindow.ShowDialog();
}
但是,如果我创造这样的:
private AboutWindow SettingsWindow = new AboutWindow();
private void button_Click(object sender, RibbonControlEventArgs e)
{
SettingsWindow.ShowDialog();
}
一切似乎是确定并没有挂用户界面。
窗口内的方法,引起的问题介绍如下:
private async void CallUpdateDownload()
{
UpdaterStatus.CurrentUpdateStatus = await DownloadAndSaveInstallerAsync(UpdaterStatus.freshVersion);
}
public static async Task<UpdateStatus> DownloadAndSaveInstallerAsync(string NewVersion)
主要挂在本字符串内DownloadAndSaveInstallerAsync
发生:
CloudBlockBlob blob = new CloudBlockBlob(new Uri(sas));
MemoryStream msRead = new MemoryStream();
blob.DownloadToStream(msRead); // HANGS HERE
问题是,为什么这个发生?为什么在开始时创建窗口会阻止它从异步方法中挂起。
另一个问题是,那我有另外一个对象,它也用DownloadAndSaveInstallerAsync
的方法。这些对象是在运行时创建的,我无法做任何事情来防止这种挂起,下载时发生。
如何防止UI挂在这种情况下(在运行时创建对象)?
下面详细代码:
private async void CallUpdateDownload()
{
UpdaterStatus.CurrentUpdateStatus = await UpdaterLogic.DownloadAndSaveInstallerAsync(UpdaterStatus.freshVersion);
}
UpdaterLogic:
public static async Task<UpdateStatus> DownloadAndSaveInstallerAsync(string NewVersion)
{
//...
if (await SaveInstallerToMemoryAsync(NewVersion))
{
return UpdateStatus.ReadyToInstall;
}
else
{
return UpdateStatus.Error;
}
}
private static async Task<bool> SaveInstallerToMemoryAsync(string NewVersion)
{
using (MemoryStream ms = await UpdaterClient.DownloadInstallerAsync(NewVersion))
using (FileStream fs = new FileStream(UpdaterSettings.Path), FileMode.Create))
{
if (ms == null) return false;
ms.Position = 0;
await ms.CopyToAsync(fs);
fs.Close();
ms.Close();
return true;
}
}
UpdaterClient:
public static async Task<MemoryStream> DownloadInstallerAsync(string version)
{
string sas = await GetInstallerDownloadLinkAsync(version);
CloudBlockBlob blob = new CloudBlockBlob(new Uri(sas));
MemoryStream msRead = new MemoryStream();
blob.DownloadToStream(msRead);
return msRead;
}
public static async Task<string> GetInstallerDownloadLinkAsync(string version)
{
HttpResponseMessage response = null;
response = await httpClient.GetAsync(UpdaterSettings.Link + version);
if (response.IsSuccessStatusCode)
{
var res = await response.Content.ReadAsStringAsync();
return res.Trim('"');
}
}
你在等待里面'DownloadAndSaveInstallerAsync'? –
创建设置窗口(在构造函数等等中)或窗口显示时,“CallUpdateDownload”方法是否运行? – mcy
里面有一个'await SaveInstallerToMemoryAsync(NewVersion)'的方法,这个头部是'private static async任务 SaveInstallerToMemoryAsync(string NewVersion)' - 这个方法可以和'blob'和'MemoryStream'一起使用 –