PropertyCollection.IDictionary.Add(Object, Object) Method

Definition

Adds an element with the provided key and value to the IDictionary object.

void IDictionary.Add (object key, object value);

Parameters

key
Object

The Object to use as the key of the element to add.

value
Object

The Object to use as the value of the element to add.

Implements

Exceptions

key is null.

An element with the same key already exists in the IDictionary object.

The IDictionary is read-only.

-or-

The IDictionary has a fixed size.

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 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);
}

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.

Applies to

منتج الإصدارات
.NET 8 (package-provided), 9 (package-provided)
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7 (package-provided), 4.7, 4.7.1 (package-provided), 4.7.1, 4.7.2 (package-provided), 4.7.2, 4.8 (package-provided), 4.8, 4.8.1
.NET Standard 2.0 (package-provided)
Windows Desktop 3.0, 3.1, 5, 6, 7, 8, 9

See also