Walkthrough: Creating a Content Service Object
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This walkthrough explores how to define the logic for a custom service to manage site content in a Windows SharePoint Services deployment. The example shows how to create classes that derive from classes in the Microsoft.SharePoint.Administration namespace to persist custom administrative settings in the database. The example includes class files that implement data structures that contain metadata about a list of locations. Each content location specifies a URL that must be preserved.
The example includes creating code files for the following classes:
ContentService Defines the top-level object, which derives from the SPService class and provides the logic for managing content locations in a deployment. This class includes constructors for initializing the ContentService object, as well as members for retrieving the content service and its collection of content locations.
ContentLocationCollection Defines a collection class that inherits from the SPPersistedChildCollection<T> class and provides an object to contain content locations. This class contains a constructor and an Add method.
ContentLocation Inherits from SPPersistedObject and defines a content location. This class includes constructors and members for custom property settings.
In addition to creating an assembly with the previous code files, the example shows how to use a custom action Feature to add a link on the Operations page so that administrators can access the service. The example also describes how to use custom .aspx pages to provide the user interface that is required for managing the content service and its content location items. For information about creating a Windows SharePoint Services project in Microsoft Visual Studio 2005, see Getting Started with Programmatically Customizing a SharePoint Web Site in Visual Studio.
ContentService Class File
The following code example defines a FormatType enumeration, and the top-level ContentService class, which includes constructors and the following members:
Local A static property to retrieve the current content location service.
Locations A static property to access the content location collection.
GetAllContentLocations A method to return all content locations provided through the service.
Format A property to get or set the type of format for the content service.
At the top of each code file that is subsequently presented, add a directive to import the Microsoft.SharePoint.Administration namespace, as in the following example. Use the Persisted attribute to make property settings persist in the database. The custom namespace that contains objects in the example is named MS.Samples.SharePoint.ContentManager.
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SharePoint.Administration
Namespace MS.Samples.SharePoint.ContentManager
Public Enum FormatType
HTML
XML
End Enum 'ContentLocationType
<System.Runtime.InteropServices.Guid("BB69A6EB-3230-43ca-B4F5-752EAC39C74A")> _
Public Class ContentService
Inherits SPService
<Persisted()> _
Private formatType As FormatType
Private Shared locations As ContentLocationCollection
Private Shared local As ContentService = Nothing
' A static property that retrieves the content service.
Public Shared ReadOnly Property Local() As ContentService
Get
If ContentService.local Is Nothing Then
ContentService.local = _
SPFarm.Local.Services.GetValue < ContentService > "ContentService"
End If
Return ContentService.local
End Get
End Property
' A static property for accessing the location collection.
Public Shared ReadOnly Property Locations() As ContentLocationCollection
Get
If Me.locations Is Nothing Then
Me.locations = New ContentLocationCollection(Me)
End If
Return Me.locations
End Get
End Property
' An empty public constructor required for serialization.
Public Sub New()
End Sub 'New
Public Sub New(farm As SPFarm)
MyBase.New("ContentService", farm)
' Add code to initialize as needed.
End Sub 'New
' A method to retrieve the content location collection.
Public Function GetAllContentLocations() As ContentLocationCollection
Dim service As ContentService = ContentService.Local
If service Is Nothing Then
Return Nothing
End If
Return service.Locations
End Function 'GetAllContentLocations
Public Property Format () As FormatType
Get
Return Me.formatType
End Get
Set
Me.formatType = value
End Set
End Property
End Class 'ContentService
End Namespace 'MS.Samples.SharePoint.ContentManager
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SharePoint.Administration;
namespace MS.Samples.SharePoint.ContentManager
{
public enum FormatType
{
HTML,
XML
}
[System.Runtime.InteropServices.Guid("BB69A6EB-3230-43ca-B4F5-752EAC39C74A")]
public class ContentService : SPService
{
[Persisted]
private FormatType formatType;
private static ContentLocationCollection locations;
private static ContentService local = null;
/* A static property that retrieves the content service. */
public static ContentService Local
{
get
{
if (ContentService.local == null)
{
ContentService.local =
SPFarm.Local.Services.GetValue<ContentService>("ContentService");
}
return ContentService.local;
}
}
/* A static property for accessing the location collection. */
public static ContentLocationCollection Locations
{
get
{
if (this.locations == null)
{
this.locations = new ContentLocationCollection(this);
}
return this.locations;
}
}
/* An empty public constructor required for serialization. */
public ContentService()
{;}
public ContentService(SPFarm farm)
: base("ContentService", farm)
{/* Add code to initialize as needed. */}
/* A method to retrieve the content location collection. */
public ContentLocationCollection GetAllContentLocations()
{
ContentService service = ContentService.Local;
if (service == null)
{
return null;
}
return service.Locations;
}
public FormatType Format
{
get
{
return this.formatType;
}
set
{
this.formatType = value;
}
}
}
}
Define a custom Provision method to add the ContentService object to the database, such as in the following example. This method can be contained in the previous ContentService class, or it can be separately contained to be more modular and callable from different contexts, such as from a Feature installer that you can create to install the service, or from a command-line operation. The Provision method adds the ContentService object to the database without requiring that you specify the assembly and class.
Note
The custom Provision method that you define is not the Provision method of the base SPPersistedObject class.
Public Sub Provision()
' Add the ContentService administration object to the database.
Dim contentService As ContentService = ContentService.Local
If contentService Is Nothing Then
contentService = New ContentService(SPFarm.Local)
contentService.Update()
End If
End Sub
public void Provision()
{
/* Add the ContentService administration object to the database. */
ContentService contentService = ContentService.Local;
if (contentService == null)
{
contentService = new ContentService(SPFarm.Local);
contentService.Update();
}
}
ContentLocationCollection Class File
The following example defines the ContentLocationCollection class, which includes constructors and an Add method for adding new content locations to the collection.
Public Class ContentLocationCollection
Public Sub New(parent As SPPersistedObject)
MyBase.New(parent)
End Sub
Public Sub Add(url As String)
Dim location As New ContentLocation(String.Empty, Me.Parent)
location.Url = url
location.Update()
End Sub
End Class
public class ContentLocationCollection : SPPersistedChildCollection<ContentLocation>
{
public ContentLocationCollection(SPPersistedObject parent) : base(parent)
{;}
public void Add(String url)
{
ContentLocation location = new ContentLocation(String.Empty, this.Parent);
location.Url = url;
location.Update();
}
}
ContentLocation Class File
The following example defines an enumeration, ContentLocationType, that specifies the type of content location, and a class, ContentLocation, that defines the properties for a content location, including its display name, type, URL, and output path. Specifying the Persisted attribute makes a property setting persist in the database.
The ContentLocation class includes the following members:
DisplayName Property to get the display name of the location.
Url Property to get or set the URL for a content location.
LocationType Property to get or set the location type.
ContentOutputPath Property to get or set an output path.
Public Enum ContentLocationType
Web
List
End Enum 'ContentLocationType
Public Class ContentLocation
Inherits SPPersistedObject
<Persisted()> _
Private locationType As ContentLocationType
<Persisted()> _
Private contentOutputPath As String
<Persisted()> _
Private url As String
Public Sub New()
End Sub 'New
Public Sub New(name As String, parent As SPPersistedObject)
MyBase.New(name, parent)
End Sub 'New
Public Overrides ReadOnly Property DisplayName() As String
Get
Return Me.url
End Get
End Property
Public Property Url() As String
Get
Return Me.url
End Get
Set
If Me.url = value Then
Return
End If
Me.url = value
' The Name property must be unique among multiple children in a
' collection. Use the URL to ensure uniqueness.
Me.Name = Me.url
End Set
End Property
Public Property LocationType() As ContentLocationType
Get
Return Me.locationType
End Get
Set
Me.locationType = value
End Set
End Property
Public Property ContentOutputPath() As String
Get
Return Me.contentOutputPath
End Get
Set
Me.contentOutputPath = value
End Set
End Property
End Class 'ContentLocation
public enum ContentLocationType
{
Web,
List
}
public class ContentLocation : SPPersistedObject
{
[Persisted]
private ContentLocationType locationType;
[Persisted]
private String contentOutputPath;
[Persisted]
private String url;
public ContentLocation()
{}
public ContentLocation(string name, SPPersistedObject parent)
: base(name, parent)
{;}
public override string DisplayName
{
get
{
return this.url;
}
}
public String Url
{
get { return this.url; }
set
{
if (this.url == value)
{
return;
}
this.url = value;
/* The Name property must be unique among multiple children in a collection. Use the URL to ensure uniqueness. */
this.Name = this.url;
}
}
public ContentLocationType LocationType
{
get { return this.locationType; }
set { this.locationType = value; }
}
public String ContentOutputPath
{
get { return this.contentOutputPath; }
set { this.contentOutputPath = value; }
}
}
Add a Custom Action and ASPX Pages
Add .aspx pages to the \Admin folder, and define their code behind in your assembly. For information on administrative .aspx pages, see Central Administration Pages. Use a Feature to add a custom action to a Central Administration page. For information on adding a custom action, see How to: Add Actions to the User Interface.
The following Elements.xml file adds a Content export custom action to the Global Configuration section of the Operations page that links to a contentman.aspx page for managing content locations.
<?xml version="1.0" encoding="utf-8" ?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
<CustomAction
Id="ContentManagement"
GroupId="GlobalConfiguration"
Location="Microsoft.SharePoint.Administration.Operations"
Sequence="31"
Title="Content export">
<UrlAction Url="/_admin/contentman.aspx" />
</CustomAction>
</Elements>
The contentman.aspx file to which the custom action points can include links to form pages for creating, displaying, or editing content location items. Code behind for the New item page, for example, can include logic like the following, which adds location items for URLs that are typed in a urlImportExport box on the page, and which redirects to the contentman.aspx page:
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SharePoint.WebControls
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace MS.Samples.SharePoint.ContentManager
Public Class NewContentImportExportPage
Inherits Page
Protected urlImportExport As InputFormTextBox
Protected Sub SaveNewImportExport(sender As Object, eventArgs As EventArgs)
Dim service As ContentService = ContentService.Local
service.Locations.Add(Me.urlImportExport.Text)
Response.Redirect("/_admin/contentman.aspx", True)
End Sub 'SaveNewImportExport
End Class 'NewContentImportExportPage
End Namespace 'MS.Samples.SharePoint.ContentManager
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SharePoint.WebControls;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MS.Samples.SharePoint.ContentManager
{
public class NewContentImportExportPage : Page
{
protected InputFormTextBox urlImportExport;
protected void SaveNewImportExport(object sender, EventArgs eventArgs)
{
ContentService service = ContentService.Local;
service.Locations.Add(this.urlImportExport.Text);
Response.Redirect("/_admin/contentman.aspx", true);
}
}
}
After you implement your custom service, you can access its data by instantiating the service and calling its members. You can also create other custom objects that inherit from other persisted objects in the Microsoft.SharePoint.Administration namespace. You can create a class, for example, that derives from the SPJobDefinition class to implement a timer job and perform timed operations through your custom service. Or you can inherit from the SPFeatureReceiver class to define event handling to register the service when it is installed or activated as a Feature.
Through persisted objects, you can add custom administration objects to the configuration database to persist the logic and data for a Web application that is built on the Windows SharePoint Services platform.