Bad data in datasource property

Hello Lukáš,

Thank you for the sample project.

To show persistent objects in a non-Persistent object's view, you need to handle the OnObjectSpaceCreated event as demonstrated in the following thread: How to: Show Persistent Objects in a Non-Persistent Object's View.

C#
using DevExpress.ExpressApp;
//...
builder.ObjectSpaceProviders.Events.OnObjectSpaceCreated = context => {
    CompositeObjectSpace compositeObjectSpace = context.ObjectSpace as CompositeObjectSpace;
    if (compositeObjectSpace != null) {
        if (!(compositeObjectSpace.Owner is CompositeObjectSpace)) {
            var objectSpaceProviderService = context.ServiceProvider.GetRequiredService<IObjectSpaceProviderService>();
            var objectSpaceCustomizerService = context.ServiceProvider.GetRequiredService<IObjectSpaceCustomizerService>();
            compositeObjectSpace.PopulateAdditionalObjectSpaces(objectSpaceProviderService, objectSpaceCustomizerService);
        }
    }
}

To populate the lookup property editor, I recommend you use ObjectSpace to get persistent objects that will be used to populate the editor:

C#
public IList<TestObject> TestObjs {
    get {
        if (testObjs == null) {
            if (Type == TestType.Type1)
                testObjs = ObjectSpace.GetObjects<TestObject>().Where(x => x.Test.StartsWith("1")).ToList();
            if (Type == TestType.Type2)
                testObjs = ObjectSpace.GetObjects<TestObject>().Where(x => x.Test.StartsWith("2")).ToList();
        }
        return testObjs;
    }
}

See the following help topic for more information: How to: Implement Cascading Filtering for Lookup List Views > Scenario 4 - Populate the Lookup Property Manually.

I attached a modified project. Please let me know if it helps.

Regards,
Fhillip