AddOrGetExisting<T>(String,T,String) Method

If an item exists in the primary or secondary cache then it is returned, otherwise it is added and null is returned. The default expiration for the primary and secondary cache providers are used.

Syntax

Visual Basic
C#
Managed Extensions for C++
C++/CLI

'Declaration
 
Public Overloads Function AddOrGetExisting(Of T)( _
   ByVal key As System.String, _
   ByVal value As T, _
   Optional ByVal region As System.String _
) As T

'Usage
 
Dim instance As SmartCache
Dim key As System.String
Dim value As T
Dim region As System.String
Dim value As T
 
value = instance.AddOrGetExisting(Of T)(key, value, region)

public T AddOrGetExisting<T>( 
   System.string key,
   T value,
   System.string region
)

public: T* AddOrGetExisting<T>( 
   System.string* key,
   T* value,
   System.string* region
)

public:
T^ AddOrGetExistinggeneric<typename T>
( 
   System.String^ key,
   T^ value,
   System.String^ region
)

Parameters

key: Key for the cache item
value: The value to insert if it does not exist
region: The region for the cache item

Type Parameters

T

Example

//Create a Primary Memory Cache with a backing File Cache
string directory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "KellermanSoftware", "NetCachingLibrary", "Tests");
SmartConfig config = new SmartConfig(new MemoryCacheProvider(), new FileCacheProvider(directory));
            
//Specify UserName and LicenseKey for Licensed Mode
//config.UserName = "my user name";
//config.LicenseKey = "my license key";
            
//Instantiate the cache
SmartCache cache = new SmartCache(config);
            
//Build parameters for the report
int month = DateTime.Now.Month;
int year = DateTime.Now.Year;
            
//Load the report from the database
List<ReportDetail> report = ReportLogic.MonthlySalesReport(month, year);
            
//Get the cache key based on the report parameters
string cacheKey = cache.BuildCacheKey("MonthlySalesReport", month, year);
            
List<ReportDetail> result = cache.AddOrGetExisting(cacheKey, report);
            
if (result == null)
	Console.WriteLine("The item was added to the cache");
else
	Console.WriteLine("The item already exists in the cache");

VB.NET

'Create a Primary Memory Cache with a backing File Cache
Dim directory As String = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "KellermanSoftware", "NetCachingLibrary", "Tests")
Dim config As New SmartConfig(New MemoryCacheProvider(), New FileCacheProvider(directory))
            
'Specify UserName and LicenseKey for Licensed Mode
'config.UserName = "my user name";
'config.LicenseKey = "my license key";
            
'Instantiate the cache
Dim cache As New SmartCache(config)
            
'Build parameters for the report
Dim month As Integer = Date.Now.Month
Dim year As Integer = Date.Now.Year
            
'Load the report from the database
Dim report As List(Of ReportDetail) = ReportLogic.MonthlySalesReport(month, year)
            
'Get the cache key based on the report parameters
Dim cacheKey As String = cache.BuildCacheKey("MonthlySalesReport", month, year)
            
Dim result As List(Of ReportDetail) = cache.AddOrGetExisting(cacheKey, report)
            
If result Is Nothing Then
	Console.WriteLine("The item was added to the cache")
Else
	Console.WriteLine("The item already exists in the cache")
End If

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

SmartCache Class
SmartCache Members
Overload List