The Hashtable class represents a collection of key-and-value pairs that are organized based on the hash code of the key. The key is used to access the items in the collection. Hashtable.ContainsKey(Object) Method is used to check whether the Hashtable contains a specific key or not.
public virtual bool ContainsKey(object key);
key: The key of type System.Object to locate in the Hashtable.
Return Type: It return true if the Hashtable contains an element with the specified key otherwise, false. The return type of this method is System.Boolean.
Exception: This method can give ArgumentNullException if the key is null.
Below given are some examples to understand the implementation in a better way:
myTable contains the key
myTable doesn't contain the key