Dictionary<TKey, TValue>.ICollection<KeyValuePair<TKey, TValue>>.Add Method
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Adds the specified value to the ICollection<T> with the specified key.
Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Private Sub Add ( _
keyValuePair As KeyValuePair(Of TKey, TValue) _
) Implements ICollection(Of KeyValuePair(Of TKey, TValue)).Add
void ICollection<KeyValuePair<TKey, TValue>>.Add(
KeyValuePair<TKey, TValue> keyValuePair
)
Parameters
- keyValuePair
Type: System.Collections.Generic.KeyValuePair<TKey, TValue>
The KeyValuePair<TKey, TValue> structure representing the key and value to add to the Dictionary<TKey, TValue>.
Implements
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | The key of keyValuePair is nulla null reference (Nothing in Visual Basic). |
| ArgumentException | An element with the same key already exists in the Dictionary<TKey, TValue>. |
Remarks
If Count is less than the capacity, this method approaches an O(1) operation. If the capacity needs to be increased to accommodate the new element, this method becomes an O(n) operation, where n is Count.
Examples
The following example shows how to use explicit interface implementations of the System.Collections.Generic.ICollection<T> generic interface to manipulate a Dictionary<TKey, TValue> object.
Imports System.Collections.Generic
Public Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
' Create a new dictionary of strings, with string keys, and
' access it through the generic ICollection interface. The
' generic ICollection interface views the dictionary as a
' collection of KeyValuePair objects with the same type
' arguments as the dictionary.
'
Dim openWith As ICollection(Of KeyValuePair(Of String, String)) _
= New Dictionary(Of String, String)
' Add some elements to the dictionary. When elements are
' added through the ICollection(Of T) interface, the keys
' and values must be wrapped in KeyValuePair objects.
'
openWith.Add(New KeyValuePair(Of String, String)("txt", "notepad.exe"))
openWith.Add(New KeyValuePair(Of String, String)("bmp", "paint.exe"))
openWith.Add(New KeyValuePair(Of String, String)("dib", "paint.exe"))
openWith.Add(New KeyValuePair(Of String, String)("rtf", "wordpad.exe"))
outputBlock.Text &= vbCrLf
For Each element As KeyValuePair(Of String, String) In openWith
outputBlock.Text &= String.Format("{0}, {1}", element.Key, element.Value) & vbCrLf
Next
' The Contains method also takes a KeyValuePair object.
'
outputBlock.Text &= String.Format(vbLf & _
"Contains(KeyValuePair(""txt"", ""notepad.exe"")): {0}", _
openWith.Contains(New KeyValuePair(Of String, String)("txt", "notepad.exe"))) & vbCrLf
' The Remove method takes a KeyValuePair object.)
'
' Use the Remove method to remove a key/value pair.
outputBlock.Text &= String.Format(vbLf & _
"Remove(New KeyValuePair(""dib"", ""paint.exe""))") & vbCrLf
openWith.Remove(New KeyValuePair(Of String, String)("dib", "paint.exe"))
outputBlock.Text &= vbCrLf
For Each element As KeyValuePair(Of String, String) In openWith
outputBlock.Text &= String.Format("{0}, {1}", element.Key, element.Value) & vbCrLf
Next
' Create an array of KeyValuePair objects and copy the
' contents of the dictionary to it. Subtract one from the
' array size because Visual Basic allocates an extra array
' element.
Dim copy(openWith.Count - 1) As KeyValuePair(Of String, String)
openWith.CopyTo(copy, 0)
' List the contents of the array.
'
outputBlock.Text &= vbCrLf
For Each element As KeyValuePair(Of String, String) In copy
outputBlock.Text &= String.Format("{0}, {1}", element.Key, element.Value) & vbCrLf
Next
End Sub
End Class
' This code example produces the following output:
'
'txt, notepad.exe
'bmp, paint.exe
'dib, paint.exe
'rtf, wordpad.exe
'
'Contains(KeyValuePair("txt", "notepad.exe")): True
'
'Remove(New KeyValuePair("dib", "paint.exe"))
'
'txt, notepad.exe
'bmp, paint.exe
'rtf, wordpad.exe
'
'txt, notepad.exe
'bmp, paint.exe
'rtf, wordpad.exe
using System;
using System.Collections.Generic;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
// Create a new dictionary of strings, with string keys, and
// access it through the generic ICollection interface. The
// generic ICollection interface views the dictionary as a
// collection of KeyValuePair objects with the same type
// arguments as the dictionary.
//
ICollection<KeyValuePair<String, String>> openWith =
new Dictionary<String, String>();
// Add some elements to the dictionary. When elements are
// added through the ICollection<T> interface, the keys
// and values must be wrapped in KeyValuePair objects.
//
openWith.Add(new KeyValuePair<String, String>("txt", "notepad.exe"));
openWith.Add(new KeyValuePair<String, String>("bmp", "paint.exe"));
openWith.Add(new KeyValuePair<String, String>("dib", "paint.exe"));
openWith.Add(new KeyValuePair<String, String>("rtf", "wordpad.exe"));
outputBlock.Text += "\n";
foreach (KeyValuePair<string, string> element in openWith)
{
outputBlock.Text += String.Format("{0}, {1}", element.Key, element.Value) + "\n";
}
// The Contains method also takes a KeyValuePair object.
//
outputBlock.Text += String.Format(
"\nContains(KeyValuePair(\"txt\", \"notepad.exe\")): {0}",
openWith.Contains(new KeyValuePair<String, String>("txt", "notepad.exe"))) + "\n";
// The Remove method takes a KeyValuePair object.)
//
// Use the Remove method to remove a key/value pair.
outputBlock.Text += String.Format("\nRemove(new KeyValuePair(\"dib\", \"paint.exe\"))") + "\n";
openWith.Remove(new KeyValuePair<String, String>("dib", "paint.exe"));
outputBlock.Text += "\n";
foreach (KeyValuePair<string, string> element in openWith)
{
outputBlock.Text += String.Format("{0}, {1}", element.Key, element.Value) + "\n";
}
// Create an array of KeyValuePair objects and copy the
// contents of the dictionary to it.
//
KeyValuePair<string, string>[] copy =
new KeyValuePair<string, string>[openWith.Count];
openWith.CopyTo(copy, 0);
// List the contents of the array.
//
outputBlock.Text += "\n";
foreach (KeyValuePair<string, string> element in copy)
{
outputBlock.Text += String.Format("{0}, {1}", element.Key, element.Value) + "\n";
}
}
}
/* This code example produces the following output:
txt, notepad.exe
bmp, paint.exe
dib, paint.exe
rtf, wordpad.exe
Contains(KeyValuePair("txt", "notepad.exe")): True
Remove(new KeyValuePair("dib", "paint.exe"))
txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe
txt, notepad.exe
bmp, paint.exe
rtf, wordpad.exe
*/
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.