PropertyCollection.IDictionary.Add(Object, Object) Method
Definition
Important
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Adds an element with the provided key and value to the IDictionary object.
virtual void System.Collections.IDictionary.Add(System::Object ^ key, System::Object ^ value) = System::Collections::IDictionary::Add;
void IDictionary.Add (object key, object value);
abstract member System.Collections.IDictionary.Add : obj * obj -> unit
override this.System.Collections.IDictionary.Add : obj * obj -> unit
Sub Add (key As Object, value As Object) Implements IDictionary.Add
Parameters
Implements
Exceptions
key
is null
.
An element with the same key already exists in the IDictionary object.
Examples
The following example shows how to implement the Add method. This code example is part of a larger example provided for the IDictionary class.
public:
virtual 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 gcnew InvalidOperationException
("The dictionary cannot hold any more items.");
}
items[itemsInUse++] = gcnew DictionaryEntry(key, value);
}
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);
}
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
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.