C# | Remove entry with specified key from OrderedDictionary (original) (raw)

Last Updated : 01 Feb, 2019

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:

Below given are some examples to understand the implementation in a better way: Example 1:

CSHARP `

// 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:

CSHARP `

// 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:

Reference:

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