C# 3.0 Object Initialation - Is there notification that the object is being initialized?
We have several domain objects which need to support both read-only and read-write modes; they currently have a bool Locked
property for this--when Locked
attempts to alter properties on the object result in an InvalidOperationException
. The default state for the objects is Locked.
The object-initialization syntax of C# 3 introduces a small issue with these, in that the object must be unlocked (or default to be unlocked) during initialization and then locked explicityly at the end.
When using C# 3's object initialization syntax is there a means of receiving notification that the object is being intitialized or that initialization is complete? System.ComponentModel.ISupportInitialize
was my best hope, but it doesn't g开发者_开发知识库et called.
You could use a fluent API and append it:
var obj = new MyType { Id = 123, Name = "abc"}.Freeze();
where the Freeze
method returns the same instance (fluent) - something like:
class MyType {
private bool isFrozen;
public MyType Freeze() {
isFrozen = true;
return this;
}
protected void ThrowIfFrozen() {
if (isFrozen) throw new InvalidOperationException("Too cold");
}
private int id;
public int Id {
get { return id; }
set { ThrowIfFrozen(); id = value; }
}
private string name;
public string Name {
get { return name; }
set { ThrowIfFrozen(); name = value; }
}
}
(you could centralize the check a bit more if needed)
No, there is no such notification mechanism. The object initializer feature will simply call the specified constructor and then set the accessible fields / properties in the order they are listed. There is no interface available which supports notifications for this feature.
No. The object initializers just are a compiler feature to assist in initializing your objects. They call the properties directly.
You need to either force constructor usage, or add a "lock" method to lock them down explicitly.
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