IDictionary.Add Method
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Adds an element with the provided key and value to the IDictionary object.
Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Sub Add ( _
key As Object, _
value As Object _
)
void Add(
Object key,
Object value
)
Parameters
- key
Type: System.Object
The Object to use as the key of the element to add.
- value
Type: System.Object
The Object to use as the value of the element to add.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | key is nulla null reference (Nothing in Visual Basic). |
| ArgumentException | An element with the same key already exists in the IDictionary object. |
| NotSupportedException | The IDictionary is read-only. -or- The IDictionary has a fixed size. |
Remarks
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 nulla null reference (Nothing in Visual Basic).
Examples
The following code example demonstrates how to implement the Add method. This code example is part of a larger example provided for the IDictionary class.
Public Sub Add(ByVal key As Object, ByVal value As Object) Implements IDictionary.Add
' Add the new key/value pair even if this key already exists in the dictionary.
If ItemsInUse = items.Length Then
Throw New InvalidOperationException("The dictionary cannot hold any more items.")
End If
items(ItemsInUse) = New DictionaryEntry(key, value)
ItemsInUse = ItemsInUse + 1
End Sub
public void Add(object key, object value)
{
// Add the new key/value pair even if this key already exists in the dictionary.
if (ItemsInUse == items.Length)
throw new InvalidOperationException("The dictionary cannot hold any more items.");
items[ItemsInUse++] = new DictionaryEntry(key, value);
}
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.