DataServiceContext.AttachTo Method (String, Object, String)
Notifies the DataServiceContext to start tracking the specified resource and supplies the location of the resource in the specified resource set.
Namespace: System.Data.Services.Client
Assembly: Microsoft.Data.Services.Client (in Microsoft.Data.Services.Client.dll)
Syntax
'Declaration
Public Sub AttachTo ( _
entitySetName As String, _
entity As Object, _
etag As String _
)
'Usage
Dim instance As DataServiceContext
Dim entitySetName As String
Dim entity As Object
Dim etag As String
instance.AttachTo(entitySetName, entity, _
etag)
public void AttachTo(
string entitySetName,
Object entity,
string etag
)
public:
void AttachTo(
String^ entitySetName,
Object^ entity,
String^ etag
)
member AttachTo :
entitySetName:string *
entity:Object *
etag:string -> unit
public function AttachTo(
entitySetName : String,
entity : Object,
etag : String
)
Parameters
- entitySetName
Type: System.String
The string value that contains the name of the entity set to which to the entity is attached.
- entity
Type: System.Object
The entity to add.
- etag
Type: System.String
An etag value that represents the state of the entity the last time it was retrieved from the data service. This value is treated as an opaque string; no validation is performed on it by the client library.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | When entitySetName is nulla null reference (Nothing in Visual Basic). -or- When entity is nulla null reference (Nothing in Visual Basic). |
| ArgumentException | When entitySetName is an empty string. -or- When the supplied object does not have a key property. |
| InvalidOperationException | When the supplied object is already being tracked by the context |
Remarks
Calling this method notifies the DataServiceContext to start tracking the specified entity and identifies the entity set to which the entity belongs.
If the entity is part of an object graph, this operation does not traverse the graph to add related objects. The object is added to the DataServiceContext in the unchanged state. The method does not validate whether the entity set specified occurs in the data service associated with the DataServiceContext.
If the overload with an etag is used, the specified etag is associated with the newly attached entity. The etag is then sent to the data service, with all subsequent update or query operations for the entity, according to HTTP semantics. Manual generation of etag values is not recommended, but this overload is provided to enable entities that may have been serialized and stored to be reattached together with relevant concurrency metadata.