C# SQLServer关闭时，SqlConnection OpenAsync会阻止UI

我有一个简单的WPF客户端应用程序（.NET4.6.2），只有一个按钮。

SqlConnection.OpenAsync

方法在执行以下步骤时阻止UI线程：

SQL Server已启动并可从客户端访问

启动客户端应用程序

单击按钮=>UI未被阻止（如预期）=>消息框显示“确定”

关闭SQL Server

单击按钮=>UI被阻止-OpenAsync阻止UI=>消息框“显示”错误

再次单击按钮=>UI未再次被阻止=>消息框显示“错误”

仅当它从单击->成功转到单击->错误OpenAsync块UI线程时。 我错过了什么

private async void按钮\u单击（对象发送方，路由目标）
{
尝试
{
使用（var conn=new SqlConnection（“..”））
{
等待连接OpenAsync（）；
}
}
捕获（系统异常）
{
MessageBox.Show（“err”）；
返回；
}
MessageBox.Show（“ok”）；
}

编辑：

挂起期间暂停调试器时调用堆栈：

System.Data.dll!SNINativeMethodWrapper.SNIOpenSyncEx(SNINativeMethodWrapper.ConsumerInfo consumerInfo, string constring, ref System.IntPtr pConn, byte[] spnBuffer, byte[] instanceName, bool fOverrideCache, bool fSync, int timeout, bool fParallel, int transparentNetworkResolutionStateNo, int totalTimeout, bool isAzureSqlServerEndpoint)    Unknown
    System.Data.dll!System.Data.SqlClient.SNIHandle.SNIHandle(SNINativeMethodWrapper.ConsumerInfo myInfo, string serverName, byte[] spnBuffer, bool ignoreSniOpenTimeout, int timeout, out byte[] instanceName, bool flushCache, bool fSync, bool fParallel, System.Data.SqlClient.TransparentNetworkResolutionState transparentNetworkResolutionState, int totalTimeout)   Unknown
    System.Data.dll!System.Data.SqlClient.TdsParserStateObject.CreatePhysicalSNIHandle(string serverName, bool ignoreSniOpenTimeout, long timerExpire, out byte[] instanceName, byte[] spnBuffer, bool flushCache, bool async, bool fParallel, System.Data.SqlClient.TransparentNetworkResolutionState transparentNetworkResolutionState, int totalTimeout) Unknown
    System.Data.dll!System.Data.SqlClient.TdsParser.Connect(System.Data.SqlClient.ServerInfo serverInfo, System.Data.SqlClient.SqlInternalConnectionTds connHandler, bool ignoreSniOpenTimeout, long timerExpire, bool encrypt, bool trustServerCert, bool integratedSecurity, bool withFailover, bool isFirstTransparentAttempt, System.Data.SqlClient.SqlAuthenticationMethod authType, bool disableTnir, System.Data.SqlClient.SqlAuthenticationProviderManager sqlAuthProviderManager)  Unknown
    System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(System.Data.SqlClient.ServerInfo serverInfo, string newPassword, System.Security.SecureString newSecurePassword, bool ignoreSniOpenTimeout, System.Data.ProviderBase.TimeoutTimer timeout, bool withFailover, bool isFirstTransparentAttempt, bool disableTnir)  Unknown
    System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(System.Data.SqlClient.ServerInfo serverInfo, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, System.Data.ProviderBase.TimeoutTimer timeout)    Unknown
    System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(System.Data.ProviderBase.TimeoutTimer timeout, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance) Unknown
    System.Data.dll!System.Data.SqlClient.SqlInternalConnectionTds.SqlInternalConnectionTds(System.Data.ProviderBase.DbConnectionPoolIdentity identity, System.Data.SqlClient.SqlConnectionString connectionOptions, System.Data.SqlClient.SqlCredential credential, object providerInfo, string newPassword, System.Security.SecureString newSecurePassword, bool redirectedUserInstance, System.Data.SqlClient.SqlConnectionString userConnectionOptions, System.Data.SqlClient.SessionData reconnectSessionData, System.Data.ProviderBase.DbConnectionPool pool, string accessToken, bool applyTransientFaultHandling, System.Data.SqlClient.SqlAuthenticationProviderManager sqlAuthProviderManager)    Unknown
    System.Data.dll!System.Data.SqlClient.SqlConnectionFactory.CreateConnection(System.Data.Common.DbConnectionOptions options, System.Data.Common.DbConnectionPoolKey poolKey, object poolGroupProviderInfo, System.Data.ProviderBase.DbConnectionPool pool, System.Data.Common.DbConnection owningConnection, System.Data.Common.DbConnectionOptions userOptions) Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(System.Data.ProviderBase.DbConnectionPool pool, System.Data.Common.DbConnection owningObject, System.Data.Common.DbConnectionOptions options, System.Data.Common.DbConnectionPoolKey poolKey, System.Data.Common.DbConnectionOptions userOptions)   Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionPool.CreateObject(System.Data.Common.DbConnection owningObject, System.Data.Common.DbConnectionOptions userOptions, System.Data.ProviderBase.DbConnectionInternal oldConnection)   Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(System.Data.Common.DbConnection owningObject, System.Data.Common.DbConnectionOptions userOptions, System.Data.ProviderBase.DbConnectionInternal oldConnection)  Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionPool.TryGetConnection(System.Data.Common.DbConnection owningObject, uint waitForMultipleObjectsTimeout, bool allowCreate, bool onlyOneCheckConnection, System.Data.Common.DbConnectionOptions userOptions, out System.Data.ProviderBase.DbConnectionInternal connection)   Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionPool.TryGetConnection(System.Data.Common.DbConnection owningObject, System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry, System.Data.Common.DbConnectionOptions userOptions, out System.Data.ProviderBase.DbConnectionInternal connection)    Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(System.Data.Common.DbConnection owningConnection, System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry, System.Data.Common.DbConnectionOptions userOptions, System.Data.ProviderBase.DbConnectionInternal oldConnection, out System.Data.ProviderBase.DbConnectionInternal connection)    Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(System.Data.Common.DbConnection outerConnection, System.Data.ProviderBase.DbConnectionFactory connectionFactory, System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry, System.Data.Common.DbConnectionOptions userOptions)  Unknown
    System.Data.dll!System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(System.Data.Common.DbConnection outerConnection, System.Data.ProviderBase.DbConnectionFactory connectionFactory, System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry, System.Data.Common.DbConnectionOptions userOptions)    Unknown
    System.Data.dll!System.Data.SqlClient.SqlConnection.TryOpenInner(System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry)  Unknown
    System.Data.dll!System.Data.SqlClient.SqlConnection.TryOpen(System.Threading.Tasks.TaskCompletionSource<System.Data.ProviderBase.DbConnectionInternal> retry)   Unknown
    System.Data.dll!System.Data.SqlClient.SqlConnection.OpenAsync(System.Threading.CancellationToken cancellationToken) Unknown
    System.Data.dll!System.Data.Common.DbConnection.OpenAsync() Unknown
>   TestWpf.exe!TestWpf.UndoManagerTest.UndoManagerTestView.Button_Click(object sender, System.Windows.RoutedEventArgs e) Line 35   C#
    PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) Unknown
    PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised)    Unknown
    PresentationCore.dll!System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args)   Unknown
    PresentationCore.dll!System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs e)  Unknown
    PresentationFramework.dll!System.Windows.Controls.Primitives.ButtonBase.OnClick()   Unknown
    PresentationFramework.dll!System.Windows.Controls.Button.OnClick()  Unknown
    PresentationFramework.dll!System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(System.Windows.Input.MouseButtonEventArgs e)    Unknown
    PresentationCore.dll!System.Windows.UIElement.OnMouseLeftButtonUpThunk(object sender, System.Windows.Input.MouseButtonEventArgs e)  Unknown
    PresentationCore.dll!System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate genericHandler, object genericTarget) Unknown
    PresentationCore.dll!System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate handler, object target)   Unknown
    PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) Unknown
    PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised)    Unknown
    PresentationCore.dll!System.Windows.UIElement.ReRaiseEventAs(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args, System.Windows.RoutedEvent newEvent)  Unknown
    PresentationCore.dll!System.Windows.UIElement.OnMouseUpThunk(object sender, System.Windows.Input.MouseButtonEventArgs e)    Unknown
    PresentationCore.dll!System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate genericHandler, object genericTarget) Unknown
    PresentationCore.dll!System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate handler, object target)   Unknown
    PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) Unknown
    PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised)    Unknown
    PresentationCore.dll!System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args)   Unknown
    PresentationCore.dll!System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs args)    Unknown
    PresentationCore.dll!System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs args, bool trusted) Unknown
    PresentationCore.dll!System.Windows.Input.InputManager.ProcessStagingArea() Unknown
    PresentationCore.dll!System.Windows.Input.InputManager.ProcessInput(System.Windows.Input.InputEventArgs input)  Unknown
    PresentationCore.dll!System.Windows.Input.InputProviderSite.ReportInput(System.Windows.Input.InputReport inputReport)   Unknown
    PresentationCore.dll!System.Windows.Interop.HwndMouseInputProvider.ReportInput(System.IntPtr hwnd, System.Windows.Input.InputMode mode, int timestamp, System.Windows.Input.RawMouseActions actions, int x, int y, int wheel)   Unknown
    PresentationCore.dll!System.Windows.Interop.HwndMouseInputProvider.FilterMessage(System.IntPtr hwnd, MS.Internal.Interop.WindowMessage msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled)   Unknown
    PresentationCore.dll!System.Windows.Interop.HwndSource.InputFilterMessage(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled)    Unknown
    WindowsBase.dll!MS.Win32.HwndWrapper.WndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) Unknown
    WindowsBase.dll!MS.Win32.HwndSubclass.DispatcherCallbackOperation(object o) Unknown
    WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs)  Unknown
    WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.TryCatchWhen(object source, System.Delegate callback, object args, int numArgs, System.Delegate catchHandler) Unknown
    WindowsBase.dll!System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, object args, int numArgs)   Unknown
    WindowsBase.dll!MS.Win32.HwndSubclass.SubclassWndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam)  Unknown
    [Native to Managed Transition]  
    [Managed to Native Transition]  
    WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame)   Unknown
    WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame frame)   Unknown
    PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore)   Unknown
    PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window)  Unknown
    PresentationFramework.dll!System.Windows.Application.Run(System.Windows.Window window)  Unknown
    PresentationFramework.dll!System.Windows.Application.Run()  Unknown
    TestWpf.exe!TestWpf.App.Main() Line 53  C#

System.Data.dll！SNINativeMethodWrapper.SNIOpenSyncEx（SNINativeMethodWrapper.ConsumerInfo ConsumerInfo，字符串分析，ref System.IntPtr pConn，byte[]spnBuffer，byte[]instanceName，bool fOverrideCache，bool fSync，int timeout，bool fParallel，int transparentNetworkResolutionStateNo，int totalTimeout，bool isAzureSqlServerEndpoint）未知
System.Data.dll！System.Data.SqlClient.SNIHandle.SNIHandle（SNINativeMethodWrapper.ConsumerInfo myInfo，string serverName，byte[]spnBuffer，bool ignoresInOpenTimeout，int timeout，out byte[]instanceName，bool flushCache，bool fSync，bool fParallel，System.Data.SqlClient.TransparentNetworkResolutionState TransparentNetworkResolutionState TransparentNetworkResolutionState，int totalTimeout）不为人知
System.Data.dll！System.Data.SqlClient.TdsParserStateObject.CreatePhysicalSNIHandle（字符串服务器名、bool IgnoresInOpenTimeout、long-TimerSpire、out字节[]instanceName、字节[]spnBuffer、bool flushCache、bool异步、bool fParallel、System.Data.SqlClient.TransparentNetworkResolutionState TransparentNetworkResolutionState、int totalTimeout）未知
System.Data.dll！System.Data.SqlClient.TdsParser.Connect（System.Data.SqlClient.ServerInfo ServerInfo，System.Data.SqlClient.SqlInternalConnectionDS connHandler，bool IgnoresInOpenTimeout，long-TimerPire，bool encrypt，bool trustServerCert，bool integratedSecurity，bool withFailover，bool IsFirstTransparentAttest，System.Data.SqlClient.SqlAuthenticationMethod authType，bool disableTnir，System.Data。SqlClient.SqlAuthenticationProviderManager（sqlAuthProviderManager）未知
System.Data.dll！System.Data.SqlClient.SqlInternalConnectionDS.AttemptOneLogin（System.Data.SqlClient.ServerInfo ServerInfo，string newPassword，System.Security.SecureString newSecurePassword，bool IgnoresInOpenTimeout，System.Data.ProviderBase.TimeoutTimer timeout，bool withFailover，bool IsFirstTransparentTest，bool disableTnir）未知
System.Data.dll！System.Data.SqlClient.sqlinternalconnectionds.LoginNoFailover（System.Data.SqlClient.ServerInfo ServerInfo、string newPassword、System.Security.SecureString newSecurePassword、bool redirectedUserInstance、System.Data.SqlClient.SqlConnectionString连接选项、System.Data.SqlClient.SqlCredential凭据、System.Data.ProviderBase.TimeoutTimer超时）未知
System.Data.dll！System.Data.SqlClient.SqlInternalConnectionDS.OpenLoginList（System.Data.ProviderBase.TimeoutTimer超时，System.Data.SqlClient.SqlConnectionString连接选项，System.Data.SqlClient.SqlCredential凭据，string新密码，System.Security.SecureString newSecurePassword，bool redirectedUserInstance）未知
System.Data.dll！System.Data.SqlClient.sqlinternalconnectionds.sqlinternalconnectionds（System.Data.ProviderBase.DbConnectionPoolIdentity、System.Data.SqlClient.SqlConnectionString连接选项、System.Data.SqlClient.SqlCredential凭据、对象providerInfo、字符串newPassword、System.Security.SecureString newSecurePassword、bool redirectedUserInstance、System.Data.SqlClient.SqlConnectionString userConnectionOptions、System.Data.SqlClient.SessionData重新连接SessionData、System.Data.ProviderBase.DbConnectionPool池、string accessToken、bool applyTransientFaultHandling、System.Data.SqlClient.SqlAuthenticationProviderManager sqlAuthProviderManager）未知
System.Data.dll！System.Data.SqlClient.SqlConnectionFactory.CreateConnection（System.Data.Common.DbConnectionOptions选项，System.Data.Common.DbConnectionPoolKey poolKey，object poolGroupProviderInfo，System.Data.ProviderBase.DbConnectionPool池，System.Data.Common.DbConnection owningConnection，System.Data.Common.DbConnectionOptions用户选项）未知
System.Data.dll！System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection（System.Data.ProviderBase.DbConnectionPool池，System.Data.Common.DbConnectionOwningObject，System.Data.Common.DbConnectionOptions选项，System.Data.Common.DbConnectionPoolKey poolKey，System.Data.Common.DbConnectionOptions用户选项）未知
System.Data.dll！System.Data.ProviderBase.DbConnectionPool.CreateObject（System.Data.Common.DbConnection owningObject、System.Data.Common.DbConnectionOptions用户选项、System.Data.ProviderBase.DbConnectionInternal oldConnection）未知
System.Data.dll！System.Data.ProviderBase.DbConnectionPool.UserCreateRequest（System.Data.Common.DbConnection owningObject、System.Data.Common.DbConnectionOptions userOptions、System.Data.ProviderBase.DbConnectionInternal oldConnection）未知
System.Data.dll！System.Data.ProviderBase.DbConnectionPool.TryGetConnection（System.Data.Common.DbConnection owningObject，uint WaitForMultipleObjectStimOut，bool allowCreate，bool OnlyonEckConnection，System.Data.Common.DbConnectionOptions用户选项，out System.Data.ProviderBase.DbConnection内部连接）
Task.Run(async () => ... await connection.OpenAsync() ...);

using (var conn = new SqlConnection("...."))   
{
    await conn.OpenAsync().ConfigureAwait(false);
}

private async void Button_Click(object sender, RoutedEventArgs e)
{
    await Task.Run(async () =>
        {
            try
            {
                using (var conn = new SqlConnection("...."))
                {
                    await conn.OpenAsync();
                }
            }
            catch (System.Exception)
            {
                MessageBox.Show("err");
                return;
            }
            MessageBox.Show("ok");
        }
    );
}

await Task.Run(async () => await conn.OpenAsync());