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ObjectContext.TryGetObjectByKey Method

Returns an object that has the specified entity key.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public bool TryGetObjectByKey(
	EntityKey key,
	out Object value
)

Parameters

key
Type: System.Data.EntityKey

The key of the object to be found.

value
Type: System.Object%

When this method returns, contains the object.

Return Value

Type: System.Boolean
true if the object was retrieved successfully. false if the key is temporary, the connection is null, or the value is null.

ExceptionCondition
ArgumentNullException

key is null.

ArgumentException

Incompatible metadata for key.

TryGetObjectByKey tries to retrieve an object that has the specified EntityKey from the ObjectStateManager. If the object is currently not loaded into the object context, a query is executed in an attempt to return the object from the data source. For more information, see Object Queries (Entity Framework).

Use the TryGetObjectByKey method to avoid handling the ObjectNotFoundException raised by GetObjectByKey when the object cannot be found.

This method will return objects in the Deleted state.

A temporary key cannot be used to return an object from the data source.

The TryGetObjectByKey(EntityKey, Object) method applies the standard .NET TryParse pattern for the GetObjectByKey method, returning false when the ObjectNotFoundException is caught.

The example in this topic is based on the Adventure Works Sales Model. The example creates an EntityKey for an entity of the given type and then tries to retrieve an entity by key.

using (AdventureWorksEntities advWorksContext =
    new AdventureWorksEntities())
{
    try
    {
        Object entity = null;
        IEnumerable<KeyValuePair<string, object>> entityKeyValues =
            new KeyValuePair<string, object>[] {
                new KeyValuePair<string, object>("SalesOrderID", 43680) };

        // Create the  key for a specific SalesOrderHeader object. 
        EntityKey key = new EntityKey("AdventureWorksEntities.SalesOrderHeader", entityKeyValues);

        // Get the object from the context or the persisted store by its key. 
        if (advWorksContext.TryGetObjectByKey(key, out entity))
        {
            Console.WriteLine("The requested " + entity.GetType().FullName + 
                " object was found");
        }
        else
        {
            Console.WriteLine("An object with this key " +
                "could not be found.");
        }
    }
    catch (EntitySqlException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1
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