Devexpress XAF class property datasource filtering

Question

i declared a class something like this

[DefaultClassOptions]
public class Test:XPObject
{
    Type _classType;

    [NonPersistent]
    public Type ClassType
    {
         get { return _classType; }
         set { SetPropertyValue("ClassType", ref _classType, value); }
    }
}

the problem is, this field is shown as a dropdown list, but i have no control on this list, i can't filter or customize this list. it always opens with all accessible types in all assemblies. neither DataSourceProperty nor DataSourceCriteria attributes worked.

i can do this with other persistent classes, but i can't do with "Type" typed fields.

if there is a workaround please help. thanks in advance.

Answer 1

Implement a LocalizedClassInfoTypeConverter descendant, as:

public class LocalizedClassInfoTypeConverter<T> : LocalizedClassInfoTypeConverter {
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) {
            List<Type> list = new List<Type>();
            foreach (Type t in base.GetStandardValues(context)) {
                if (typeof(T).IsAssignableFrom(t)) list.Add(t);
            }
            return new StandardValuesCollection(list);
        }
    }

Then use it as follows:

[DefaultClassOptions]
public class Test:XPObject
{
    Type _classType;
    [ValueConverter(typeof(TypeToStringConverter))]
    [TypeConverter(typeof(LocalizedClassInfoTypeConverter<MyBaseTypeOrInterface>))]
    public Type ClassType
    {
         get { return _classType; }
         set { SetPropertyValue("ClassType", ref _classType, value); }
    }

}

Source: https://www.devexpress.com/Support/Center/Question/Details/Q364986