ListDictionary.Remove(Object) method is used to remove the entry with the specified key from the ListDictionary.
Syntax:
public void Remove (object key);
Here, key is the key of the entry which is to be removed.
Exception: This method will give ArgumentNullException if the key is null.
Below are the examples to illustrate the use of ListDictionary.Remove(Object) Method:
Example 1:
// C# code to remove the entry with // the specified key from the ListDictionary using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a ListDictionary named myDict
ListDictionary myDict = new ListDictionary();
// Adding key/value pairs in myDict
myDict.Add( "Australia" , "Canberra" );
myDict.Add( "Belgium" , "Brussels" );
myDict.Add( "Netherlands" , "Amsterdam" );
myDict.Add( "China" , "Beijing" );
myDict.Add( "Russia" , "Moscow" );
myDict.Add( "India" , "New Delhi" );
// To get count of key/value pairs in myDict
Console.WriteLine( "Total key/value pairs in myDict are : " + myDict.Count);
// Displaying the key/value pairs in myDict
Console.WriteLine( "The key/value pairs in myDict are : " );
foreach (DictionaryEntry de in myDict)
{
Console.WriteLine(de.Key + " " + de.Value);
}
// Remove the entry with the specified
// key from the ListDictionary
myDict.Remove( "Russia" );
// To get count of key/value pairs in myDict
Console.WriteLine( "Total key/value pairs in myDict are : " + myDict.Count);
// Displaying the key/value pairs in myDict
Console.WriteLine( "The key/value pairs in myDict are : " );
foreach (DictionaryEntry de in myDict)
{
Console.WriteLine(de.Key + " " + de.Value);
}
}
} |
Output:
Total key/value pairs in myDict are : 6 The key/value pairs in myDict are : Australia Canberra Belgium Brussels Netherlands Amsterdam China Beijing Russia Moscow India New Delhi Total key/value pairs in myDict are : 5 The key/value pairs in myDict are : Australia Canberra Belgium Brussels Netherlands Amsterdam China Beijing India New Delhi
Example 2 :
// C# code to remove the entry with // the specified key from the ListDictionary using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a ListDictionary named myDict
ListDictionary myDict = new ListDictionary();
// Adding key/value pairs in myDict
myDict.Add( "I" , "first" );
myDict.Add( "II" , "second" );
myDict.Add( "III" , "third" );
myDict.Add( "IV" , "fourth" );
myDict.Add( "V" , "fifth" );
// To get count of key/value pairs in myDict
Console.WriteLine( "Total key/value pairs in myDict are : " + myDict.Count);
// Displaying the key/value pairs in myDict
Console.WriteLine( "The key/value pairs in myDict are : " );
foreach (DictionaryEntry de in myDict)
{
Console.WriteLine(de.Key + " " + de.Value);
}
// Remove the entry with the specified
// key from the ListDictionary
// This should raise "ArgumentNullException"
// as the key is null
myDict.Remove( null );
// To get count of key/value pairs in myDict
Console.WriteLine( "Total key/value pairs in myDict are : " + myDict.Count);
// Displaying the key/value pairs in myDict
Console.WriteLine( "The key/value pairs in myDict are : " );
foreach (DictionaryEntry de in myDict)
{
Console.WriteLine(de.Key + " " + de.Value);
}
}
} |
Runtime Error:
Unhandled Exception:
System.ArgumentNullException: Key cannot be null.
Parameter name: key
Note:
- If the ListDictionary does not contain an element with the specified key, the ListDictionary remains unchanged. No exception is thrown.
- This method is an O(n) operation, where n is Count.
Reference :