Specifies the default value for the ReadOnlyAttribute, which is No (that is, the property this attribute is bound to is read/write). This static field is read-only.
public static readonly ReadOnlyAttribute Default
When you mark a property with this value, this attribute is set to the constant member No. Therefore, when you want to check whether the attribute is set to this value in your code, you must specify the attribute as ReadOnlyAttribute.No.