NameObjectCollectionBase.BaseGetKey(Int32) Method
Definition
Important
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Gets the key of the entry at the specified index of the NameObjectCollectionBase instance.
protected:
System::String ^ BaseGetKey(int index);
protected string BaseGetKey (int index);
protected string? BaseGetKey (int index);
member this.BaseGetKey : int -> string
Protected Function BaseGetKey (index As Integer) As String
Parameters
- index
- Int32
The zero-based index of the key to get.
Returns
A String that represents the key of the entry at the specified index.
Exceptions
index
is outside the valid range of indexes for the collection.
Examples
The following code example uses BaseGetKey and BaseGet to get specific keys and values.
#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
public ref class MyCollection : public NameObjectCollectionBase {
private:
DictionaryEntry^ _de;
// Gets a key-and-value pair (DictionaryEntry) using an index.
public:
property DictionaryEntry^ default[ int ] {
DictionaryEntry^ get( int index ) {
_de->Key = this->BaseGetKey( index );
_de->Value = this->BaseGet( index );
return( _de );
}
}
// Gets or sets the value associated with the specified key.
property Object^ default[ String^ ] {
Object^ get(String^ key) {
return( this->BaseGet( key ) );
}
void set( String^ key, Object^ value ) {
this->BaseSet( key, value );
}
}
// Adds elements from an IDictionary into the new collection.
MyCollection( IDictionary^ d ) {
_de = gcnew DictionaryEntry();
for each ( DictionaryEntry^ de in d ) {
this->BaseAdd( (String^) de->Key, de->Value );
}
}
};
public ref class SamplesNameObjectCollectionBase {
public:
static void Main() {
// Creates and initializes a new MyCollection instance.
IDictionary^ d = gcnew ListDictionary();
d->Add( "red", "apple" );
d->Add( "yellow", "banana" );
d->Add( "green", "pear" );
MyCollection^ myCol = gcnew MyCollection( d );
Console::WriteLine( "Initial state of the collection (Count = {0}):", myCol->Count );
PrintKeysAndValues( myCol );
// Gets specific keys and values.
Console::WriteLine( "The key at index 0 is {0}.", myCol[0]->Key );
Console::WriteLine( "The value at index 0 is {0}.", myCol[0]->Value );
Console::WriteLine( "The value associated with the key \"green\" is {0}.", myCol["green"] );
}
static void PrintKeysAndValues( MyCollection^ myCol ) {
for ( int i = 0; i < myCol->Count; i++ ) {
Console::WriteLine( "[{0}] : {1}, {2}", i, myCol[i]->Key, myCol[i]->Value );
}
}
};
int main()
{
SamplesNameObjectCollectionBase::Main();
}
/*
This code produces the following output.
Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
The key at index 0 is red.
The value at index 0 is apple.
The value associated with the key "green" is pear.
*/
using System;
using System.Collections;
using System.Collections.Specialized;
public class MyCollection : NameObjectCollectionBase {
private DictionaryEntry _de = new DictionaryEntry();
// Gets a key-and-value pair (DictionaryEntry) using an index.
public DictionaryEntry this[ int index ] {
get {
_de.Key = this.BaseGetKey( index );
_de.Value = this.BaseGet( index );
return( _de );
}
}
// Gets or sets the value associated with the specified key.
public Object this[ String key ] {
get {
return( this.BaseGet( key ) );
}
set {
this.BaseSet( key, value );
}
}
// Adds elements from an IDictionary into the new collection.
public MyCollection( IDictionary d ) {
foreach ( DictionaryEntry de in d ) {
this.BaseAdd( (String) de.Key, de.Value );
}
}
}
public class SamplesNameObjectCollectionBase {
public static void Main() {
// Creates and initializes a new MyCollection instance.
IDictionary d = new ListDictionary();
d.Add( "red", "apple" );
d.Add( "yellow", "banana" );
d.Add( "green", "pear" );
MyCollection myCol = new MyCollection( d );
Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
// Gets specific keys and values.
Console.WriteLine( "The key at index 0 is {0}.", myCol[0].Key );
Console.WriteLine( "The value at index 0 is {0}.", myCol[0].Value );
Console.WriteLine( "The value associated with the key \"green\" is {0}.", myCol["green"] );
}
public static void PrintKeysAndValues( MyCollection myCol ) {
for ( int i = 0; i < myCol.Count; i++ ) {
Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value );
}
}
}
/*
This code produces the following output.
Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
The key at index 0 is red.
The value at index 0 is apple.
The value associated with the key "green" is pear.
*/
Imports System.Collections
Imports System.Collections.Specialized
Public Class MyCollection
Inherits NameObjectCollectionBase
Private _de As New DictionaryEntry()
' Gets a key-and-value pair (DictionaryEntry) using an index.
Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
Get
_de.Key = Me.BaseGetKey(index)
_de.Value = Me.BaseGet(index)
Return _de
End Get
End Property
' Gets or sets the value associated with the specified key.
Default Public Property Item(key As [String]) As [Object]
Get
Return Me.BaseGet(key)
End Get
Set
Me.BaseSet(key, value)
End Set
End Property
' Adds elements from an IDictionary into the new collection.
Public Sub New(d As IDictionary)
Dim de As DictionaryEntry
For Each de In d
Me.BaseAdd(CType(de.Key, [String]), de.Value)
Next de
End Sub
End Class
Public Class SamplesNameObjectCollectionBase
Public Shared Sub Main()
' Creates and initializes a new MyCollection instance.
Dim d = New ListDictionary()
d.Add("red", "apple")
d.Add("yellow", "banana")
d.Add("green", "pear")
Dim myCol As New MyCollection(d)
Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
' Gets specific keys and values.
Console.WriteLine("The key at index 0 is {0}.", myCol(0).Key)
Console.WriteLine("The value at index 0 is {0}.", myCol(0).Value)
Console.WriteLine("The value associated with the key ""green"" is {0}.", myCol("green"))
End Sub
Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
Dim i As Integer
For i = 0 To myCol.Count - 1
Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
Next i
End Sub
End Class
'This code produces the following output.
'
'Initial state of the collection (Count = 3):
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'The key at index 0 is red.
'The value at index 0 is apple.
'The value associated with the key "green" is pear.
Remarks
This method is an O(1) operation.
Applies to
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