XamlTypeInvoker.AddToCollection(Object, Object) Method
Definition
Important
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Adds the provided item to an instance of the type that is relevant to this XamlTypeInvoker.
public:
virtual void AddToCollection(System::Object ^ instance, System::Object ^ item);
public virtual void AddToCollection (object instance, object item);
abstract member AddToCollection : obj * obj -> unit
override this.AddToCollection : obj * obj -> unit
Public Overridable Sub AddToCollection (instance As Object, item As Object)
Parameters
- instance
- Object
An instance of the type specified by the XamlType used for constructing this XamlTypeInvoker.
- item
- Object
The item to add.
Exceptions
Invoked this method on a XamlTypeInvoker that is based on an unknown XamlType.
-or-
Invoked this method on a XamlTypeInvoker where the relevant type is not a collection.
instance
is null
.
GetAddMethod(XamlType) for this XamlTypeInvoker returns null
.
Remarks
You should only call this method on a XamlType that represents a collection.
Notes to Inheritors
The base implementation includes a call to the internal helper ThrowIfUnknown
. This helper always throws for cases where a XamlTypeInvoker is based on an unknown XamlType, which includes cases where the UnderlyingType of the XamlType is null
.
Internally, the base implementation calls IsCollection, and throws if the result is false
.
The base implementation does not necessarily use its own GetAddMethod(XamlType) implementation. First, a cast of instance
to IList is attempted. If this succeeds, a call to Add(Object) is made and the method returns. Otherwise, the base implementation uses CLR Invoke(Object, Object[]) to invoke the underlying Add
method, as obtained from a call to GetAddMethod(XamlType) for this XamlTypeInvoker.
In the base implementation no exception is raised at this level if item
is null
. It is still possible that the underlying Add
method will raise an exception when invoked. Other run time exceptions are possible if ItemType does not return a valid result.
Applies to
.NET
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