OrderedDictionary.Remove(Object) method is used to remove entry with the specified key from the OrderedDictionary collection.
Syntax:
public void Remove (object key);
Here, key is the key of the entry to remove.
Exceptions:
- NotSupportedException : If the OrderedDictionary collection is read-only.
- ArgumentNullException : If the key is null.
Below given are some examples to understand the implementation in a better way:
Example 1:
// C# code to remove the entry // with the specified key from // the OrderedDictionary using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver method
public static void Main()
{
// Creating a orderedDictionary named myDict
OrderedDictionary myDict = new OrderedDictionary();
// Adding key and value in myDict
myDict.Add( "key1" , "value1" );
myDict.Add( "key2" , "value2" );
myDict.Add( "key3" , "value3" );
myDict.Add( "key4" , "value4" );
myDict.Add( "key5" , "value5" );
// Displaying the number of element initially
Console.WriteLine( "Number of elements are : " + myDict.Count);
// Displaying the elements in myDict
foreach (DictionaryEntry de in myDict)
Console.WriteLine(de.Key + " -- " + de.Value);
// Removing the entry with the specified
// key from the OrderedDictionary
myDict.Remove( "key2" );
// Displaying the number of element initially
Console.WriteLine( "Number of elements are : " + myDict.Count);
// Displaying the elements in myDict
foreach (DictionaryEntry de in myDict)
Console.WriteLine(de.Key + " -- " + de.Value);
}
} |
Output:
Number of elements are : 5 key1 -- value1 key2 -- value2 key3 -- value3 key4 -- value4 key5 -- value5 Number of elements are : 4 key1 -- value1 key3 -- value3 key4 -- value4 key5 -- value5
Example 2:
// C# code to remove the entry // with the specified key from // the OrderedDictionary using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver method
public static void Main()
{
// Creating a orderedDictionary named myDict
OrderedDictionary myDict = new OrderedDictionary();
// Adding key and value in myDict
myDict.Add( "A" , "Apple" );
myDict.Add( "B" , "Banana" );
myDict.Add( "C" , "Cat" );
myDict.Add( "D" , "Dog" );
// Displaying the number of element initially
Console.WriteLine( "Number of elements are : " + myDict.Count);
// Displaying the elements in myDict
foreach (DictionaryEntry de in myDict)
Console.WriteLine(de.Key + " -- " + de.Value);
// Removing the entry with the specified
// key from the OrderedDictionary
// This should raise "ArgumentNullException"
// as the key is null
myDict.Remove( null );
// Displaying the number of element initially
Console.WriteLine( "Number of elements are : " + myDict.Count);
// Displaying the elements in myDict
foreach (DictionaryEntry de in myDict)
Console.WriteLine(de.Key + " -- " + de.Value);
}
} |
Runtime Error:
Unhandled Exception:
System.ArgumentNullException: Value cannot be null.
Parameter name: key
Note:
- The entries that follow the removed entry move up to occupy the vacated spot and the indexes of the entries that get moved are also updated.
- If the OrderedDictionary collection does not contain an entry with the specified key, the OrderedDictionary remains unchanged and no exception is thrown.
Reference: