Modal qml dialog from c++ with QT 5.7

Locate

I want to invoke a modal Dialog from the c++ part of my program under QT 5.7. If there is only one Text in my qml for the Dialog, I get the Dialog. But after I will set the Dialog to modal or after inserting a second Item I get an exception (read Access Violation)

my qml part:

import QtQuick 2.5
import QtQuick.Controls 2.0
import QtQuick.Dialogs 1.2

Dialog {
    title: "Test dialog"
    visible: true;
    modality : Qt.ApplicationModal
    standardButtons: StandardButton.Ok

    property string name: ""
    property string password: ""


    contentItem:
        Rectangle {
            implicitWidth: 400
            implicitHeight: 100

            Text {
                id: userLoginText
                text: "Please enter your login data."
            }

            Text {
                id: userNameText
                anchors.top: userLoginText.bottom
                text: "Username"
            }

            TextField {
                id: userNameInput
                anchors.top: userNameText.bottom
                focus: true
                text: name
                onTextChanged: name = text
            }
        
            Text {
                id: passwordText
                anchors.top: userNameInput.bottom
                text: "Password"
            }
        
            TextField {
                id: passwordInput
                anchors.top: passwordText.bottom
                echoMode: TextInput.Password
                onTextChanged: password = text
            }
    }
}

and my c++ part:

void DlgUserData::Show()
{
    QQuickWindow *itm = qobject_cast<QQuickWindow*>(_engine->rootObjects().value(0));

    QQmlComponent component(_engine, QUrl(QStringLiteral("qrc:/camUserData.qml")));
    _dlgItem = qobject_cast<QObject*>(component.create());
    _dlgItem->setParent(itm);

    _dlgItem->setProperty("name", _name);
    _dlgItem->setProperty("password", _password);
}

_engine is a pointer to my QQmlApplicationEngine instance.

p3c0

@Locate You should always check if the cast was successful and that you get access to that object which in your case fails and thus memory access error.
Instead try the following:

QObject *obj =  engine.rootObjects().first();
obj->setProperty("name", _name);

Locate

Thanks, that solved my Problem.