HttpApplicationState Class
Enables sharing of global information across multiple sessions and requests within an ASP.NET application.
System.Collections.Specialized.NameObjectCollectionBase
System.Web.HttpApplicationState
Namespace: System.Web
Assembly: System.Web (in System.Web.dll)
The HttpApplicationState type exposes the following members.
| Name | Description | |
|---|---|---|
 | AllKeys | Gets the access keys in the HttpApplicationState collection. |
| Contents | Gets a reference to the HttpApplicationState object. |
| Count | Gets the number of objects in the HttpApplicationState collection. (Overrides NameObjectCollectionBase.Count.) |
| Item[Int32] | Gets a single HttpApplicationState object by index. |
| Item[String] | Gets the value of a single HttpApplicationState object by name. |
| Keys | Gets a NameObjectCollectionBase.KeysCollection instance that contains all the keys in the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
| StaticObjects | Gets all objects declared by an <object> tag where the scope is set to "Application" within the ASP.NET application. |
| Name | Description | |
|---|---|---|
| Add | Adds a new object to the HttpApplicationState collection. |
| Clear | Removes all objects from an HttpApplicationState collection. |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited from Object.) |
| Get(Int32) | Gets an HttpApplicationState object by numerical index. |
| Get(String) | Gets an HttpApplicationState object by name. |
| GetEnumerator | Returns an enumerator that iterates through the NameObjectCollectionBase. (Inherited from NameObjectCollectionBase.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetKey | Gets an HttpApplicationState object name by index. |
| GetObjectData | Implements the ISerializable interface and returns the data needed to serialize the NameObjectCollectionBase instance. (Inherited from NameObjectCollectionBase.) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| Lock | Locks access to an HttpApplicationState variable to facilitate access synchronization. |
| OnDeserialization | Implements the ISerializable interface and raises the deserialization event when the deserialization is complete. (Inherited from NameObjectCollectionBase.) |
| Remove | Removes the named object from an HttpApplicationState collection. |
| RemoveAll | Removes all objects from an HttpApplicationState collection. |
| RemoveAt | Removes an HttpApplicationState object from a collection by index. |
| Set | Updates the value of an object in an HttpApplicationState collection. |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| UnLock | Unlocks access to an HttpApplicationState variable to facilitate access synchronization. |
| Name | Description | |
|---|---|---|
| ICollection.CopyTo | Copies the entire NameObjectCollectionBase to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from NameObjectCollectionBase.) |
 | ICollection.IsSynchronized | Gets a value indicating whether access to the NameObjectCollectionBase object is synchronized (thread safe). (Inherited from NameObjectCollectionBase.) |
| ICollection.SyncRoot | Gets an object that can be used to synchronize access to the NameObjectCollectionBase object. (Inherited from NameObjectCollectionBase.) |
An ASP.NET application is the sum of all files, pages, handlers, modules, and code within the scope of a virtual directory and its subdirectories on a single Web server.
A single instance of an HttpApplicationState class is created the first time a client requests any URL resource from within a particular ASP.NET application virtual directory. A separate single instance is created for each ASP.NET application on a Web server. A reference to each instance is then exposed via the intrinsic Application object.
Application state is not shared across either a Web farm (in which an application is hosted across multiple servers) or a Web garden (in which an application is hosted across multiple processes on the same computer).
| Topic | Location |
|---|---|
| How to: Save Values in Application State | Building ASP .NET Web Applications |
| How to: Read Values from Application State | Building ASP .NET Web Applications |
| How to: Save Values in Application State | Building ASP .NET Web Applications |
| How to: Read Values from Application State | Building ASP .NET Web Applications |
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
