EntityConnection Constructor (String)


Initializes a new instance of the EntityConnection class, based on the connection string.

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

new : 
        connectionString:string -> EntityConnection


Type: System.String

The provider-specific connection string.

Exception Condition

An invalid connection string keyword has been provided, or a required connection string keyword has not been provided.

The generate a named connection string that is stored in the application's configuration file. This named connection string can be supplied in place of the connectionString parameter when you instantiate the EntityConnection class.

To avoid inadvertently putting objects System.Data.Common.CommandTrees and ObjectContext out of sync with their metadata, EntityConnection must lock its metadata. No changes to the connection string are allowed after the metadata is locked. The following are two scenarios in which metadata is locked:

  • The EntityConnection instance is constructed through the default constructor, or through this constructor (EntityConnection(String)), which accepts a connection string. In either case the connection string might be changed multiple times before the connection is opened. Calling M:System.Data.EntityClient.EntityConnection.Open() or M:System.Data.EntityClient.EntityConnection.GetMetadataWorkspace() locks the metadata.

  • The EntityConnection instance is constructed through the EntityConnection(MetadataWorkspace, DbConnection) constructor, which accepts a MetadataWorkspace and a DbConnection. In this case the metadata is locked at construction time. No changes to the connection string are ever allowed.

When metadata is loaded, the EntityConnection verifies that the conceptual model, the storage model, and the mapping file are all present.

For code examples, see Working with EntityClient.

.NET Framework
Available since 3.5
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