C# | Check if OrderedDictionary collection contains a specific key
OrderedDictionary.Contains(Object) method is used to check whether the OrderedDictionary collection contains a specific key or not.
Syntax:
public bool Contains (object key);
Here, key is the key to locate in the OrderedDictionary collection.
Return Value: This method returns True if the OrderedDictionary collection contains an element with the specified key, otherwise, False.
Below given are some examples to understand the implementation in a better way:
Example 1:
// C# code to check if OrderedDictionary // collection contains a specific key 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" ); // Checking if OrderedDictionary // collection contains a specific key Console.WriteLine(myDict.Contains( "Key6" )); } } |
Output:
False
Example 2:
// C# code to check if OrderedDictionary // collection contains a specific key 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 key/value pairs in myDict foreach (DictionaryEntry de in myDict) Console.WriteLine(de.Key + " --> " + de.Value); // Checking if OrderedDictionary collection // contains a specific key if (myDict.Contains( "key4" )) myDict.Remove( "key4" ); // Displaying the key/value pairs in myDict foreach (DictionaryEntry de in myDict) Console.WriteLine(de.Key + " --> " + de.Value); } } |
Output:
key1 --> value1 key2 --> value2 key3 --> value3 key4 --> value4 key5 --> value5 key1 --> value1 key2 --> value2 key3 --> value3 key5 --> value5
Note: Using the Item[Object] property can return a null value if the key does not exist or if the key is null. Use the Contains method to determine if a specific key exists in the OrderedDictionary collection.
Reference:
https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.ordereddictionary.contains?view=netframework-4.7.2