Hashtable.Contains(Object) Method is used to check whether the Hashtable contains a specific key or not.
public virtual bool Contains (object key);
Here, key is the Key of Object type which is to be located in the Hashtable.
Return Value: This method returns true if the Hashtable contains an element with the specified key otherwise returns false.
Exception: This method will give ArgumentNullException if the key is null.
- Hashtable.ContainsKey(Object) Method is also used to check whether the Hashtable contains a specific key or not. This method behaves same as Contains() method.
- Contains method implements IDictionary.Contains. It behaves exactly as ContainsKey and this method is an O(1) operation.
Below programs illustrate the use of above-discussed method:
System.ArgumentNullException: Key cannot be null.
Parameter name: key