Is it possible to serialize views?

DiskHumm

I'm making an app where the order and properties of the views on a page can be changed. I'm trying to serialize the StackLayout that contains the views.

I've tried 3 different serialization techniques, all of which have failed with the following exceptions:

XmlSerializer:

System.InvalidOperationException: There was an error reflecting type 'AppProject.MyApp'. occurred

Newtonsoft.Json:

Newtonsoft.Json.JsonSerializationException: Self referencing loop detected for property 'ParentView' with type 'Xamarin.Forms.StackLayout'. Path 'Pages[0].stack.Children[0]'.

BinaryFormatter:

System.Runtime.Serialization.SerializationException: Type 'AppProject.MyApp' in Assembly 'AppProject, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

Can someone please recommend a solution?

Thanks.

DiskHumm

I was actually able to serialize the views by using:

            JsonSerializerSettings settings = new JsonSerializerSettings
            {
                PreserveReferencesHandling = PreserveReferencesHandling.Objects,
                Formatting = Formatting.Indented,
                TypeNameHandling = TypeNameHandling.All
            };

            string json = JsonConvert.SerializeObject(myApp, settings);

However, when deserializing with myApp = JsonConvert.DeserializeObject<MyApp>(newjson, settings); I get the this error:

System.InvalidOperationException: Cannot change ObservableCollection during a CollectionChanged event.

Does anyone know a way around this?

Thanks.

DiskHumm

bump

JoeManke

Rather than literally serializing the view, I would define a model object(s) that describe the layout and then you create a view according to that model.

I'm freehanding this so excuse any syntax issues, but basically take this JSON:

[
    {
        "Type":"Button",
        "Text":"Click Me"
    },
    {
        "Type":"Entry",
        "Text":"Type in Me"
    },
    {
        "Type":"Label",
        "Text":"Read Me"
    }
]

And do this:

var stack = new StackLayout();
foreach(JObject item in JArray.Parse(json))
{
    View child;
    switch((string)item["Type"])
    {
        case "Button":
        {
            child = new Button
            {
                Text = (string)item["Text"]
            };
            break;
        }
        case "Entry":
        {
            child = new Entry
            {
                Text = (string)item["Text"]
            };
            break;
        }
        case "Label"
        {
            child = new Label
            {
                Text = (string)item["Text"]
            };
            break;
        }
    }

    stack.Children.Add(child);
}

JamesLavery

As @joemanke says - just serialize the view structure - this is far more lightweight. Otherwise you are serializing huge amounts of internal view data which is not relevant and is likely to be out of date or even wrong when you try to deserialize and use it.