Hashtable.Item[Object] Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets the value associated with the specified key.
public:
virtual property System::Object ^ default[System::Object ^] { System::Object ^ get(System::Object ^ key); void set(System::Object ^ key, System::Object ^ value); };public virtual object this[object key] { get; set; }public virtual object? this[object key] { get; set; }member this.Item(obj) : obj with get, setDefault Public Overridable Property Item(key As Object) As ObjectParameters
- key
- Object
The key whose value to get or set.
Property Value
The value associated with the specified key. If the specified key is not found, attempting to get it returns null, and attempting to set it creates a new element using the specified key.
Implements
Exceptions
key is null.
The property is set and the Hashtable is read-only.
-or-
The property is set, key does not exist in the collection, and the Hashtable has a fixed size.
Remarks
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 Hashtable; for example, myCollection["myNonexistentKey"] = myValue. However, if the specified key already exists in the Hashtable, setting the Item[] property overwrites the old value. In contrast, the Add method does not modify existing elements.
A key cannot be null, but a value can be. To distinguish between null that is returned because the specified key is not found and null that is returned because the value of the specified key is null, use the Contains method or the ContainsKey method to determine if the key exists in the list.
Retrieving the value of this property is an O(1) operation; setting the property is also an O(1) operation.
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.
