Sys.Data.DataContext Class

Provides facilities for read-write scenarios when using data providers such as WCF Web services or ADO.NET data services. The DataContext class supports change tracking and saving changes back to the service.

Namespace: Sys.Data

Inherits: Sys.Component

Implements: Sys.Data.IDataProvider

var MyDataContext = new Sys.Data.DataContext();

Constructors

Name	Description
Sys.Data.DataContext Constructor	Initializes a new instance the DataContext class.

Members

Name	Description
Sys.Data.DataContext.abortSave Method	Aborts the current Sys.Data.DataContext.saveChanges Method request.
Sys.Data.DataContext.addLink Method	Adds a link from one entity to another. Used in the case of many-to-many associations between entities.
Sys.Data.DataContext.clearChanges Method	Clears any tracked changes without committing them.
Sys.Data.DataContext.clearData Method	Clears the stored entities and clears tracked changes.
Sys.Data.DataContext.createEntity Method	Creates a JavaScript object for an entity of type entitySetName.
Sys.Data.DataContext.dispose Method	Disposes of the DataContext object.
Sys.Data.DataContext.fetchData Method	Fetches data from the provided service URI.
Sys.Data.DataContext.fetchDeferredProperty Method	Fetches data for a deferred property of an entity.
Sys.Data.DataContext.getIdentity Method	Gets the unique identity for an entity.
Sys.Data.DataContext.getNewIdentity Method	Generates a new identity for a new entity.
Sys.Data.DataContext.initialize Method	Called when the DataContext object is initialized.
Sys.Data.DataContext.insertEntity Method	Inserts a JavaScript object into the DataContext object. The DataContext object will then provide change tracking services on the object.
Sys.Data.DataContext.isDeferredProperty Method	Determines if the given entity and property name refer to a deferred link to another entity that has not been loaded yet.
Sys.Data.DataContext.removeEntity Method	Removes an entity from the Sys.Data.DataContext object, so that the object is no longer tracked by the DataContext for changes or identity management.
Sys.Data.DataContext.removeLink Method	Removes a link between two entities. Used in the case of many-to-many associations between entities.
Sys.Data.DataContext.saveChanges Method	Saves pending changes that were made to the current data being tracked by the Sys.Data.DataContext object.
Sys.Data.DataContext.setLink Method	Sets a link (or removes a link) between two entities. Used in the case of one-to-many associations between entities.
Sys.Data.DataContext.trackData Method	Loads the given data into the DataContext object as if it were loaded using the fetchData method.
Sys.Data.DataContext.updated Method	Called after the DataContext object has been initialized.
Sys.Data.DataContext.changes Property	Gets the current list of changes.
Sys.Data.DataContext.createEntityMethod Property	Gets or sets a JavaScript function used by the createEntity method for creating new entities.
Sys.Data.DataContext.fetchDataMethod Property	Gets or sets a JavaScript function used by the fetchData method to retrieve data.
Sys.Data.DataContext.getDeferredPropertyFetchOperationMethod Property	Gets or sets a JavaScript function used by the fetchDeferredProperty method to retrieve data. By setting this property you can provide a different implementation for fetching deferred properties.
Sys.Data.DataContext.getIdentityMethod Property	Gets or sets a JavaScript function used by the getIdentity method to provide a unique identity for an entity.
Sys.Data.DataContext.getNewIdentityMethod Property	Gets or sets a JavaScript function used by the getNewIdentity method to provide a new unique identity for an entity that has been created.
Sys.Data.DataContext.handleSaveChangesResultsMethod Property	Gets or sets the method that is called when a save operation completes.
Sys.Data.DataContext.hasChanges Property	Gets a boolean value indicating whether the DataContext has some changes on the objects which it is currently tracking.
Sys.Data.DataContext.isDeferredPropertyMethod Property	Gets or sets the method that determines if an entity field is currently a deferred entity link placeholder object.
Sys.Data.DataContext.isSaving Property	Gets a boolean value indicating whether the data is currently being saved.
Sys.Data.DataContext.items Property	Gets a dictionary of containing all the objects currently being tracked by the DataContext. The entities are keyed by their unique identities provided by the JavaScript function specified by the getIdentityMethod property.
Sys.Data.DataContext.lastFetchDataResults Property	Gets the last data that was retrieved successfully in a fetchData request.
Sys.Data.DataContext.mergeOption Property	Gets or sets a MergeOption value.
Sys.Data.DataContext.saveChangesMethod Property	Gets or sets a JavaScript function used by the saveChanges method to save data changes back to the service.
Sys.Data.DataContext.saveChangesTimeout Property	Gets or sets an integer representing a time limit used when saving changes.
Sys.Data.DataContext.saveHttpVerb Property	Gets or sets the HTTP method to be used by the Web request used for calling the saveChangesOperation on the service.
Sys.Data.DataContext.saveOperation Property	Gets or sets a string specifying the service operation to be used for saving changes.
Sys.Data.DataContext.saveParameters Property	Gets or sets a dictionary of parameters passed to the saveChangesOperation when saving changes.
Sys.Data.DataContext.serviceUri Property	Gets or sets a string indicating the service URI of the service to be used for retrieve data or for saving changes.

Example

The following example shows how to create a DataContext object and use it declaratively with a template.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="https://www.w3.org/1999/xhtml">

<head>
    <title>Read-write, with DataContext</title>
    <link href="styles/list.css" rel="stylesheet" type="text/css" />
    
    <script type="text/javascript" src="../MicrosoftAjax/MicrosoftAjax.debug.js"></script>
    <script type="text/javascript" src="../MicrosoftAjax/MicrosoftAjaxTemplates.debug.js"></script>
    <script type="text/javascript" src="../MicrosoftAjax/MicrosoftAjaxDataContext.debug.js"></script>
    <script type="text/javascript">
        var dataContext = $create(
            Sys.Data.DataContext,
            {
                serviceUri: "../Services/ImagesWcfService.svc",
                saveOperation: "SaveImages"
            }
        );
    </script>
 </head>

<body xmlns:sys="javascript:Sys"
      xmlns:dataview="javascript:Sys.UI.DataView"

    <ul class="list sys-template"
        sys:attach="dataview"
        dataview:autofetch="true"
        dataview:dataprovider="{{ dataContext }}"
        dataview:fetchoperation="GetImages"
        dataview:fetchparameters="{{ {orderBy: 'Name'} }}"
    >
        <li>
            <span>{{ Name }}</span>
            <span class="value">{{ Description }}</span>
        </li>
    </ul>
</body>
</html>

See Also

Other Resources

Language Reference