WinRT: Fix native MessageBox not closing

The message box buttons need to be added inside the XAML thread.
Otherwise QWinRTMessageDialogHelper::onCompleted will not be triggered.

To successfully emit the clicked signal across different threads do not
exit the eventloop.

Change-Id: Ie884bdfe0dc64132559755083dae50c2aa43d80b
Task-number: QTBUG-48209
Reviewed-by: Oliver Wolff <oliver.wolff@theqtcompany.com>

1 files changed, 39 insertions, 39 deletions

diff --git a/src/plugins/platforms/winrt/qwinrtmessagedialoghelper.cpp b/src/plugins/platforms/winrt/qwinrtmessagedialoghelper.cpp
index 68bf1fdcac..bb04144563 100644
--- a/src/plugins/platforms/winrt/qwinrtmessagedialoghelper.cpp
+++ b/src/plugins/platforms/winrt/qwinrtmessagedialoghelper.cpp
@@ -133,45 +133,46 @@ bool QWinRTMessageDialogHelper::show(Qt::WindowFlags windowFlags, Qt::WindowModa
         RETURN_FALSE_IF_FAILED("Failed to create dialog");
     }
 
-    // Add Buttons
-    ComPtr<IVector<IUICommand *>> dialogCommands;
-    hr = dialog->get_Commands(&dialogCommands);
-    RETURN_FALSE_IF_FAILED("Failed to get dialog commands");
-
-    // If no button is specified we need to create one to get close notification
-    int buttons = options->standardButtons();
-    if (buttons == 0)
-        buttons = Ok;
-
-    for (int i = FirstButton; i < LastButton; i<<=1) {
-        if (!(buttons & i))
-            continue;
-        // Add native command
-        const QString label = d->theme->standardButtonText(i);
-        HStringReference nativeLabel(reinterpret_cast<LPCWSTR>(label.utf16()), label.size());
-        ComPtr<IUICommand> command;
-        hr = commandFactory->Create(nativeLabel.Get(), &command);
-        RETURN_FALSE_IF_FAILED("Failed to create message box command");
-        ComPtr<IInspectable> id = Make<CommandId>(static_cast<StandardButton>(i));
-        hr = command->put_Id(id.Get());
-        RETURN_FALSE_IF_FAILED("Failed to set command ID");
-        hr = dialogCommands->Append(command.Get());
-        if (hr == E_BOUNDS) {
-            qErrnoWarning(hr, "The WinRT message dialog supports a maximum of three buttons");
-            continue;
-        }
-        RETURN_FALSE_IF_FAILED("Failed to append message box command");
-        if (i == Abort || i == Cancel || i == Close) {
-            quint32 size;
-            hr = dialogCommands->get_Size(&size);
-            RETURN_FALSE_IF_FAILED("Failed to get command list size");
-            hr = dialog->put_CancelCommandIndex(size - 1);
-            RETURN_FALSE_IF_FAILED("Failed to set cancel index");
+    hr = QEventDispatcherWinRT::runOnXamlThread([this, d, options, commandFactory, dialog]() {
+        HRESULT hr;
+
+        // Add Buttons
+        ComPtr<IVector<IUICommand *>> dialogCommands;
+        hr = dialog->get_Commands(&dialogCommands);
+        RETURN_HR_IF_FAILED("Failed to get dialog commands");
+
+        // If no button is specified we need to create one to get close notification
+        int buttons = options->standardButtons();
+        if (buttons == 0)
+            buttons = Ok;
+
+        for (int i = FirstButton; i < LastButton; i<<=1) {
+            if (!(buttons & i))
+                continue;
+            // Add native command
+            const QString label = d->theme->standardButtonText(i);
+            HStringReference nativeLabel(reinterpret_cast<LPCWSTR>(label.utf16()), label.size());
+            ComPtr<IUICommand> command;
+            hr = commandFactory->Create(nativeLabel.Get(), &command);
+            RETURN_HR_IF_FAILED("Failed to create message box command");
+            ComPtr<IInspectable> id = Make<CommandId>(static_cast<StandardButton>(i));
+            hr = command->put_Id(id.Get());
+            RETURN_HR_IF_FAILED("Failed to set command ID");
+            hr = dialogCommands->Append(command.Get());
+            if (hr == E_BOUNDS) {
+                qErrnoWarning(hr, "The WinRT message dialog supports a maximum of three buttons");
+                continue;
+            }
+            RETURN_HR_IF_FAILED("Failed to append message box command");
+            if (i == Abort || i == Cancel || i == Close) {
+                quint32 size;
+                hr = dialogCommands->get_Size(&size);
+                RETURN_HR_IF_FAILED("Failed to get command list size");
+                hr = dialog->put_CancelCommandIndex(size - 1);
+                RETURN_HR_IF_FAILED("Failed to set cancel index");
+            }
         }
-    }
 
-    hr = QEventDispatcherWinRT::runOnXamlThread([this, d, dialog]() {
-        HRESULT hr;
         ComPtr<IAsyncOperation<IUICommand *>> op;
         hr = dialog->ShowAsync(&op);
         RETURN_HR_IF_FAILED("Failed to show dialog");
@@ -206,8 +207,7 @@ HRESULT QWinRTMessageDialogHelper::onCompleted(IAsyncOperation<IUICommand *> *as
     Q_UNUSED(status);
     Q_D(QWinRTMessageDialogHelper);
 
-    if (d->loop.isRunning())
-       d->loop.exit();
+    QEventLoopLocker locker(&d->loop);
 
     d->shown = false;