我正在用C#编写Visual Studio扩展,并且在管理异常和显示错误消息时出现奇怪的行为。基本上,我只想向异常消息添加一些细节,以帮助我在出现问题时进行调查。
全部从上下文菜单项上的命令开始,我怀疑它可能与异步/等待机制背后的线程管理有关。但是我不确定我猜对了,也找不到任何解决方案。帮助!
它从我的菜单项回调开始:
internal sealed class My_RunAnalysis
{
//...
private async void MenuItemCallbackAsync(object sender, EventArgs e)
{
await My_ViewModel.RunAnalysisAsync();
}
}
//...
class My_ViewModel
{
async public static Task RunAnalysisAsync()
{
try
{
//...
await My_Model.GetResultsListAsync();
//...
}
catch (My_Exception e)
{
MessageBox.Show(e.message, e.title, MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
}
//...
class My_Model
async public static Task GetResultsListAsync()
{
ResultsList = new My_ResultsList();
var rawResultsList = await QueryServerAsync<RawResultsListResponse>("GET", My_Request.GetResults());
//...
}
async public static Task<JsonResponse> QueryServerAsync<JsonResponse>(string method,
string request)
{
try
{
HttpResponseMessage response;
switch (method)
{
case "GET":
response = await _httpClient.GetAsync(request);
break;
case "POST":
default:
StringContent httpContent = new StringContent("", Encoding.UTF8, "application/json");
response = await _httpClient.PostAsync(request, httpContent);
break;
}
if (!response.IsSuccessStatusCode) //<<<<<<CASE #1
{
throw new My_Exception(
response.ReasonPhrase,
"Exception while querying server for " + request);
}
string serializedJson = await response.Content.ReadAsStringAsync();
// CASE #2>>>>>
var jsonResponse = serializer.Deserialize<JsonResponse>(serializedJson);
return jsonResponse;
}
catch (Exception e)
{
throw new My_Exception(
e.Message,
"Exception while querying server for " + request);
}
}
奇怪的是:
如果在情况#1中发生错误,并且我创建了一个自定义异常(我的服务器已响应,但是有内部错误,并且我有一个干净的错误代码),则My_ViewModel :: RunAnalysisAsync()捕获中的MessageBox将立即正确显示。
如果在#2情况下发生本机异常(我的服务器响应格式错误的json,并且我从serializer.Deserialize收到异常),则My_ViewModel :: RunAnalysisAsync()捕获的MessageBox将不会显示,IDE将挂起15秒钟左右,然后重新启动(仍然不显示MessageBox)。
知道有什么问题吗?
谢谢!
使用await JoinableTaskFactory.SwitchToMainThreadAsync();
切换到主线程JoinableTaskFactory
是AsyncPackage
的成员。如果仍然不起作用,请尝试
public static void ShowMessageBox(string title, string text)
{
Microsoft.VisualStudio.Shell.ThreadHelper.ThrowIfNotOnUIThread();
IVsUIShell uiShell = Microsoft.VisualStudio.Shell.ServiceProvider.GlobalProvider.GetService(typeof(SVsUIShell)) as IVsUIShell;
Guid clsid = Guid.Empty;
int result;
Microsoft.VisualStudio.ErrorHandler.ThrowOnFailure(uiShell.ShowMessageBox(
0,
ref clsid,
title,
text,
string.Empty,
0,
OLEMSGBUTTON.OLEMSGBUTTON_OK,
OLEMSGDEFBUTTON.OLEMSGDEFBUTTON_FIRST,
OLEMSGICON.OLEMSGICON_INFO,
0, // false
out result));
}