Invalid property assignment error in DLL but not QT creator

[Lord Bytor]

Unfortunately this dll being used by a game engine rather than an app so I can't really run it from creator or launch it from the command line. I based it loosely off of the quickrendercontrol example but as a dll rather than app

[JKSH]

@Lord-Bytor said in Invalid property assignment error in DLL but not QT creator:

Unfortunately this dll being used by a game engine rather than an app so I can't really run it from creator or launch it from the command line.

Then do the first part of Step #2. Are your Qt DLLs being loaded from the folder(s) that you expect?

[Lord Bytor]

Well it looks like all dll's are running from the correct location with the exception of Qt5Svg.dll which path is from perforce instead. That dll exists at the expected folder, so I'm puzzled as to why it's using preforce's copy instead.

[JKSH]

@Lord-Bytor said in Invalid property assignment error in DLL but not QT creator:

path is from perforce

Check your PATH. Make sure that the PATH does not contain any folders which contains Qt DLLs. (This is the #1 cause of strange loading issues)

[Lord Bytor]

@JKSH Fixed path, doesn't load Qt5Svg.dll at all but my example still loads.. still doesn't recognize color in hex format and Qt.rgba does nothing to change color of text or background

[JKSH]

@Lord-Bytor said in Invalid property assignment error in DLL but not QT creator:

still doesn't recognize color in hex format and Qt.rgba does nothing to change color of text or background

Hmm... very strange.

Are you able to create and deploy a small QML app that has coloured background and text?

[Lord Bytor]

So I built a small window example

import QtQuick 2.2
import QtQuick.Window 2.2

Window {
    width: 640
    height: 480
    visible: true
    color: "#67ee62"
    title: qsTr("Hello World")

    Text {
        id: text1
        color: "#f63c3c"
        text: qsTr("Text")
        font.pixelSize: 12
    }
}

deployed and application works
updated qml of my dll to use the same and I get

qrc:/rendercontrol/demo.qml:2:1: module "QtQuick.Window" is not installed : 

I have QT += quick in the .pro file of dll and deploying the same as app, but getting very different results

[JKSH]

@Lord-Bytor said in Invalid property assignment error in DLL but not QT creator:

I have QT += quick in the .pro file

This only affects compilation; it does not contribute to deployment.

qrc:/rendercontrol/demo.qml:2:1: module "QtQuick.Window" is not installed

...

deploying the same as app, but getting very different results

Inspect every single file in the deployment folders of your example app and your big DLL. Ensure that all the files that were deployed with your example app also exist when you deploy your DLL (including qmldir files).

Also, try cleaning your project (delete the "build" folder) and build it again from scratch before deploying.

[Lord Bytor]

@JKSH Well, I've checked and rebuilt multiple times beyond comparing all folders, I think there is just some sort of issue running this in a DLL maybe in how Unity takes in DLLs. I may just have to go with a different solution.

[JKSH]

@Lord-Bytor said in Invalid property assignment error in DLL but not QT creator:

maybe in how Unity takes in DLLs

I just remembered: You Unity app's working directory is probably different from your DLL's location, so Qt can't find the QML modules. If you want to check, record the results of QDir::currentPath() from your DLL and from your small window example app.

Anyway, call QQmlEngine::addImportPath() to tell Qt where to find the QML modules: https://stackoverflow.com/questions/35352930/qt5-qml-module-is-not-installed/49326965#49326965

[Lord Bytor]

@JKSH Well, progress in that I'm getting a new error "Cannot load library D:\Dev\UnityProjects\QT experiment\Assets\Plugins\QtQuick.2\qtquick2plugin.dll: The specified module could not be found" that dll is present at that exact location though

Edit: Dependency walker shows it needs QT5Quick.dll, QT5Core etc... but those are all in its parent folder as produced by windeployqt