We’ve recently managed to migrate all our product lines from CSLA 3.7 to CSLA 4.0 and here are problem/solutions scenarios.
- Problem:
Class contains backend field, but is not registered
If you don’t do it, exception Csla.PropertyLoadException will be raised with message
Property load or set failed for property MyField (Properties with private backing fields must be marked as RelationshipTypes.PrivateField)
Solution:
Register backend field:
private int _my_field;
private static readonly PropertyInfo<int> MyFieldProperty = RegisterProperty<int>(o => o.MyField, "My field", RelationshipTypes.PrivateField);
public int MyField
{
get { return GetProperty(MyFieldProperty, _my_field); }
set { SetProperty(MyFieldProperty, ref _my_field, value); }
}
Problem:
Method LoadProperty was used like this:
<p>LoadProperty(MyFieldProperty, 10);</p>
exception Csla.PropertyLoadException will be raised with message “Csla.PropertyLoadException: Property load or set failed for property MyField (Attempt to read/load private field property in managed properties.) —> System.InvalidOperationException: Attempt to read/load private field property in managed propertiesâ€
In this case, you have to initialize backend field :
_my_field = 10;
- Problem :
Class contains readonly field ,
private readonly int _my_field;
and you try to set the value using binding, runtime exception raised with message:
“Expression must be writeable Parameter name: leftâ€â€œExpression must be writeable Parameter name: leftâ€
Solution:
Solution:
Make field static
private static readonly int _my_field;
- Problem:
Class is inherited from base class :
[Serializable]
public class MyBaseClass<T> : BusinessBase<T> where T : MyBaseClass<T>
{
}
[Serializable]
public class MyConcreteClass : MyBaseClass<MyConcreteClass>
{
protected static PropertyInfo<string> ConcretePropProperty = RegisterProperty(typeof(MyConcreteClass), new PropertyInfo<string>("ConcretePropProperty"));
public string ConcreteProp
{
get { return GetProperty(ConcretePropProperty); }
set { SetProperty(ConcretePropProperty, value); }
}
}
and if properties in MyBaseClass are not registered exception raised with message:
The type initializer for ‘MyConcreteClass’ threw an exception.System.TypeInitializationException: The type initializer for ‘ MyConcreteClass’ threw an exception. —> System.InvalidOperationException: Cannot register property ConcretePropr after containing type (MyBaseClass) has been instantiated
Solution:
You have to register every property in concrete class.
- Problem:
Class is inherited from BusinessListBase or BusinessBindingListBase. Adding new items in collection cannot be done.
Solution:
All items that will be added to collection must be created like child.
Did you have issues and would you like to share with community ?
