MemoryCache.AddOrGetExisting Method
Definition
Important
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Inserts a cache entry into the cache.
Overloads
| AddOrGetExisting(CacheItem, CacheItemPolicy) |
Adds a cache entry into the cache using the specified CacheItem instance and details about how to evict the entry. |
| AddOrGetExisting(String, Object, DateTimeOffset, String) |
Adds a cache entry into the cache using the specified key and a value and an absolute expiration value. |
| AddOrGetExisting(String, Object, CacheItemPolicy, String) |
Inserts a cache entry into the cache using the specified key and value and the specified details for how it is to be evicted. |
Remarks
The AddOrGetExisting method overloads are used to insert a cache entry into the cache. If a cache entry with a matching key does not exist, these methods insert a new entry. If a cache entry with a matching key already exists, they return the existing entry.
AddOrGetExisting(CacheItem, CacheItemPolicy)
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
Adds a cache entry into the cache using the specified CacheItem instance and details about how to evict the entry.
public:
override System::Runtime::Caching::CacheItem ^ AddOrGetExisting(System::Runtime::Caching::CacheItem ^ item, System::Runtime::Caching::CacheItemPolicy ^ policy);public override System.Runtime.Caching.CacheItem AddOrGetExisting (System.Runtime.Caching.CacheItem item, System.Runtime.Caching.CacheItemPolicy policy);override this.AddOrGetExisting : System.Runtime.Caching.CacheItem * System.Runtime.Caching.CacheItemPolicy -> System.Runtime.Caching.CacheItemPublic Overrides Function AddOrGetExisting (item As CacheItem, policy As CacheItemPolicy) As CacheItemParameters
- item
- CacheItem
The object to add.
- policy
- CacheItemPolicy
An object that contains eviction details for the cache entry. This object provides more options for eviction than a simple absolute expiration.
Returns
If a cache entry with the same key exists, the existing cache entry; otherwise, null.
Exceptions
The Value property is null.
Both the absolute and sliding expiration values for the CacheItemPolicy object are set to values other than the defaults of InfiniteAbsoluteExpiration and NoSlidingExpiration fields. The MemoryCache class cannot set expiration policy based on a combination of an absolute expiration and a sliding expiration. Only one expiration setting can be explicitly set when you use the MemoryCache instance. The other expiration setting must be set to InfiniteAbsoluteExpiration field or NoSlidingExpiration field.
The SlidingExpiration property is set to a value less than Zero.
-or-
The SlidingExpiration property is set to a value greater than one year.
-or-
The Priority property is not a value of the CacheItemPriority enumeration.
Remarks
The item parameter supplies the key and the value that is used by the method. If the cache has a cache entry with the same key as the key of the item parameter, the method returns the existing entry as a CacheItem instance. If there is no existing cache entry, the method creates a new one by using the key and value supplied by the item parameter, and with the eviction details specified by policy.
Warning
The Add and AddOrGetExisting method overloads do not support the UpdateCallback property. Therefore, to set the UpdateCallback property for a cache entry, use the Set method overloads instead.
Applies to
AddOrGetExisting(String, Object, DateTimeOffset, String)
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
Adds a cache entry into the cache using the specified key and a value and an absolute expiration value.
public override object AddOrGetExisting (string key, object value, DateTimeOffset absoluteExpiration, string regionName = default);override this.AddOrGetExisting : string * obj * DateTimeOffset * string -> objPublic Overrides Function AddOrGetExisting (key As String, value As Object, absoluteExpiration As DateTimeOffset, Optional regionName As String = Nothing) As ObjectParameters
- key
- String
A unique identifier for the cache entry to add.
- value
- Object
The data for the cache entry.
- absoluteExpiration
- DateTimeOffset
The fixed date and time at which the cache entry will expire.
- regionName
- String
A named region in the cache to which a cache entry can be added. Do not pass a value for this parameter. This parameter is null by default, because the MemoryCache class does not implement regions.
Returns
If a cache entry with the same key exists, the existing cache entry; otherwise, null.
Exceptions
value is not null.
regionName is not null.
Both the absolute and sliding expiration values for the CacheItemPolicy object are set to values other than the defaults of InfiniteAbsoluteExpiration and NoSlidingExpiration fields. The MemoryCache class cannot set expiration policy based on a combination of an absolute expiration and a sliding expiration. Only one expiration setting can be explicitly set when you use the MemoryCache instance. The other expiration setting must be set to InfiniteAbsoluteExpiration or NoSlidingExpiration
The SlidingExpiration property is set to a value less than Zero.
-or-
The SlidingExpiration property is set to a value greater than one year.
-or-
The Priority property is not a value of the CacheItemPriority enumeration.
Remarks
If the cache does not have a cache entry whose key matches the key parameter, a new cache entry is created, and the MemoryCache.AddOrGetExisting method overload returns null. If a matching cache entry exists, the existing entry is returned.
Warning
The Add and AddOrGetExisting method overloads do not support the UpdateCallback property. Therefore, to set the UpdateCallback property for a cache entry, use the Set method overloads instead.
Applies to
AddOrGetExisting(String, Object, CacheItemPolicy, String)
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
- Source:
- MemoryCache.cs
Inserts a cache entry into the cache using the specified key and value and the specified details for how it is to be evicted.
public override object AddOrGetExisting (string key, object value, System.Runtime.Caching.CacheItemPolicy policy, string regionName = default);override this.AddOrGetExisting : string * obj * System.Runtime.Caching.CacheItemPolicy * string -> objPublic Overrides Function AddOrGetExisting (key As String, value As Object, policy As CacheItemPolicy, Optional regionName As String = Nothing) As ObjectParameters
- key
- String
A unique identifier for the cache entry to add or get.
- value
- Object
The data for the cache entry.
- policy
- CacheItemPolicy
An object that contains eviction details for the cache entry. This object provides more options for eviction than a simple absolute expiration.
- regionName
- String
A named region in the cache to which a cache entry can be added. Do not pass a value for this parameter. By default, this parameter is null, because the MemoryCache class does not implement regions.
Returns
If a matching cache entry already exists, a cache entry; otherwise, null.
Exceptions
value is null.
Both the absolute and sliding expiration values of CacheItemPolicy object are set to values other than the defaults of InfiniteAbsoluteExpiration and NoSlidingExpiration. The MemoryCache class cannot set expiration policy based on a combination of both an absolute and a sliding expiration. Only one expiration setting can be explicitly set when you use the MemoryCache class. The other setting must be set to InfiniteAbsoluteExpiration or NoSlidingExpiration.
-or-
Both the removal callback and the update callback have been specified for CacheItemPolicy. The MemoryCache only supports using one type of callback per cache entry.
The SlidingExpiration property is set to a value less than Zero.
-or-
The SlidingExpiration has been set to a value greater than one year.
-or-
The Priority property is not a value of the CacheItemPriority enumeration.
Remarks
Warning
The Add and AddOrGetExisting method overloads do not support the UpdateCallback property. Therefore, to set the UpdateCallback property for a cache entry, use the Set method overloads instead.
