OrderedDictionary::Contains Method
Determines whether the OrderedDictionary collection contains a specific key.
Assembly: System (in System.dll)
Parameters
- key
- Type: System::Object
The key to locate in the OrderedDictionary collection.
Return Value
Type: System::Booleantrue if the OrderedDictionary collection contains an element with the specified key; otherwise, false.
Implements
IDictionary::Contains(Object)Using the Item property can return a null value if the key does not exist or if the key is nullptr. Use the Contains method to determine if a specific key exists in the OrderedDictionary collection.
Starting with the .NET Framework 2.0, this method uses the collection’s objects’ Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.
The following code example demonstrates the modification of an OrderedDictionary collection. In this example, the Contains method is used to determine if an entry exists before attempting to remove it. This code is part of a larger code example that can be viewed at OrderedDictionary.
// Modifying the OrderedDictionary if (!myOrderedDictionary->IsReadOnly) { // Insert a new key to the beginning of the OrderedDictionary myOrderedDictionary->Insert(0, "insertedKey1", "insertedValue1"); // Modify the value of the entry with the key "testKey2" myOrderedDictionary["testKey2"] = "modifiedValue"; // Remove the last entry from the OrderedDictionary: "testKey3" myOrderedDictionary->RemoveAt(myOrderedDictionary->Count - 1); // Remove the "keyToDelete" entry, if it exists if (myOrderedDictionary->Contains("keyToDelete")) { myOrderedDictionary->Remove("keyToDelete"); } }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.