Client Object model CRUD

The Client OM works by sending an XML Request. The server will return a JSON response which is converted to the appropriate Object Model.

Supported Languages

Following are the programming language/platforms supported for Client Object Model:

• .NET Languages (C#, VB.NET etc.)
• Silverlight
• Scripting Languages (JavaScript, Jscript)

Core Assemblies

There are two assemblies to be referred for working with the Client Object Model.

1. Microsoft.SharePoint.Client.dll
2. Microsoft.SharePoint.Client.Runtime.dll

These assemblies can be found in the 14 Hive folder: %ProgramFiles%\Common Files\Microsoft Shared\web server extensions\14\ISAPI.

Classes inside Client Object Model

In C#, comparing with classes of the Server Object Model, we can see that Client Object Model has similar classes with a suffix in the namespace and no SP prefix in the class name.
For example: SPSite in the Server Object Model is represented in the Client OM as Site with namespace Microsoft.SharePoint.Client.

Client Object Model	Server Object Model
Microsoft.SharePoint.Client.ClientContext	SPContext
Microsoft.SharePoint.Client.Site	SPSite
Microsoft.SharePoint.Client.Web	SPWeb
Microsoft.SharePoint.Client.List	SPList

 

More Examples with Client Object Model

Here I would like to list some examples using the Client Object Model. For starting with the examples, please do the following:

1. Create a Windows Application
2. Change the Target Framework to .NET 4.0
3. Add reference to Microsoft.SharePoint.Client, Microsoft.SharePoint.Client.Runtime

Before continuing with the examples, please ensure the site has valid data items in the Tasks list. We will be changing the data items during our session.

1. Get List Items

Here we are querying the list items of the Tasks list.

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ClientContext context = new ClientContext(ServerText.Text);
List list = context.Web.Lists.GetByTitle("Tasks");
CamlQuery query = new CamlQuery();
query.ViewXml = "<View/>";
ListItemCollection items = list.GetItems(query);

context.Load(list);
context.Load(items);

context.ExecuteQuery();

After executing the code, the result can be stored into a DataTable as shown below.

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DataTable table = new DataTable();
table.Columns.Add("Id");
table.Columns.Add("Title");

foreach (ListItem item in items)
    table.Rows.Add(item.Id, item["Title"]);

datagrid.DataSource = table;

On my machine, the data retrieved is shown below:

2. Update List Items

Here I would like to show the modification code. All the titles are appended with two asterisks whose IDs are even number.

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ClientContext context = new ClientContext(ServerText.Text);
List list = context.Web.Lists.GetByTitle("Tasks");
CamlQuery query = new CamlQuery();
query.ViewXml = "<View/>";
ListItemCollection items = list.GetItems(query);

context.Load(items);

context.ExecuteQuery();

foreach(ListItem item in items)
    if ((item.Id % 2) == 0)
    {
        item["Title"] += "**";
        item.Update();
    }

context.ExecuteQuery();

After executing the query, please refresh the data grid using the Get Data button. You can see the following result.

You can see that the Titles are modified for those with even number IDs.

 

3.Insert an item

Here we can try inserting a new item into the Tasks list.

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ClientContext context = new ClientContext(ServerText.Text);
Web web = context.Web;

List list = web.Lists.GetByTitle("Tasks");

ListItemCreationInformation newItem = new ListItemCreationInformation();
ListItem listItem = list.AddItem(newItem);
listItem["Title"] = "New Item Created through C#";
listItem.Update();

context.ExecuteQuery();

You can see that we are using a new class named ListItemCreationInformation along with the ListItem class. This information will be recorded and passed to the server once the ExecuteQuery() method is called.
On executing the above code and retrieving the results, you can see the output as below:

6. Update an Item

The Update operation is next in the series of the CRUD pattern. Already we have seen updating the Title. Here you can see how to update the Status.

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ClientContext context = new ClientContext(ServerText.Text);
List list = context.Web.Lists.GetByTitle("Tasks");
CamlQuery query = new CamlQuery();
query.ViewXml = "<View/>";

ListItemCollection listItems = list.GetItems(query);

context.Load(listItems);

context.ExecuteQuery();

ListItem item = listItems[listItems.Count - 1];
item["Status"] = "In Progress";
item.Update();

context.ExecuteQuery();

On executing the code, you can see that the last item was updated.

7. Delete an Item

Now we can try deleting an item from the List. Here is the code to achieve that.

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ClientContext context = new ClientContext(ServerText.Text);
List list = context.Web.Lists.GetByTitle("Tasks");

ListItemCollection listItems = list.GetItems(new CamlQuery() { ViewXml = "<View/>" });
context.Load(listItems);
context.ExecuteQuery();

listItems[listItems.Count - 1].DeleteObject();
context.ExecuteQuery();

We need to call the DeleteObject() method of the item followed by the ExecuteQuery().

 

10. Specifying Credentials

You can specify user credentials while accessing the SharePoint server. The property Credentials is for this purpose.

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ClientContext context = new ClientContext(ServerText.Text);
context.Credentials = new NetworkCredential("User", "Password");

Web web = context.Web;
context.Load(web);

context.ExecuteQuery();
MessageBox.Show(web.Title);