IDictionary::Item Property
Gets or sets the element with the specified key.
Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Parameters
- key
- Type: System::Object
The key of the element to get or set.
| Exception | Condition |
|---|---|
| ArgumentNullException | key is nullptr. |
| NotSupportedException | The property is set and the IDictionary object is read-only. -or- The property is set, key does not exist in the collection, and the IDictionary has a fixed size. |
This property provides the ability to access a specific element in the collection by using the following syntax: myCollection[key].
You can also use the Item property to add new elements by setting the value of a key that does not exist in the dictionary (for example, myCollection["myNonexistentKey"] = myValue). However, if the specified key already exists in the dictionary, setting the Item property overwrites the old value. In contrast, the Add method does not modify existing elements.
Implementations can vary in whether they allow the key to be nullptr.
The C# language uses the this keyword to define the indexers instead of implementing the Item property. Visual Basic implements Item as a default property, which provides the same indexing functionality.
The following code example demonstrates how to implement the Item property. This code example is part of a larger example provided for the IDictionary class.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.