C# | Check the HybridDictionary for a specific key
HybridDictionary.Contains(Object) method is used to determine whether the HybridDictionary contains a specific key or not.
Syntax:
public bool Contains (object key);
Here, key is the key to locate in the HybridDictionary.
Return Value: This method will return True if the HybridDictionary contains an entry with the specified key, otherwise, False.
Exception: The method throws ArgumentNullException if the key is null.
Below are the programs to illustrate the use of HybridDictionary.Contains(Object) method:
Example 1:
// C# code to check whether the // HybridDictionary contains a specific key. using System; using System.Collections; using System.Collections.Specialized; class GFG { // Driver code public static void Main() { // Creating a HybridDictionary named myDict HybridDictionary myDict = new HybridDictionary(); // Adding key/value pairs in myDict myDict.Add( "A" , "Apple" ); myDict.Add( "B" , "Banana" ); myDict.Add( "C" , "Cat" ); myDict.Add( "D" , "Dog" ); myDict.Add( "E" , "Elephant" ); myDict.Add( "F" , "Fish" ); // To check whether the HybridDictionary // contains "G". Console.WriteLine(myDict.Contains( "G" )); // To check whether the HybridDictionary // contains "B". Console.WriteLine(myDict.Contains( "B" )); } } |
Output:
False True
Example 2:
// C# code to check whether the // HybridDictionary contains a specific key. using System; using System.Collections; using System.Collections.Specialized; class GFG { // Driver code public static void Main() { // Creating a HybridDictionary named myDict HybridDictionary myDict = new HybridDictionary(); // 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 check whether the HybridDictionary // contains "null". This should raise // "ArgumentNullException" as key is null Console.WriteLine(myDict.Contains( null )); } } |
Runtime Error:
Unhandled Exception:
System.ArgumentNullException: Key cannot be null.
Parameter name: key
Note: This method is an O(1) operation.
Reference:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.hybriddictionary.contains?view=netframework-4.7.2