SharePoint 2010 - Configurable Web Part Properties

WebPart Properties
All Web Parts share a set of common properties that allow you to specify attributes for the appearance, layout, and other information. To view web part properties, click on the web part menu and select Edit web part".

On the right hand side you can see the web part properties window opens. Here you can make the basic changes like adjusting height, width, Title, etc.

Configurable WebPart Properties
Apart from the default properties, you may want to add you own custom properties which can be even used as parameters for the webpart. Configurable Web Parts are used to present a user-friendly interface for Web Parts configuration. The following attributes makes it possible to add custom properties.

The WebBrowsableAttribute class

The WebBrowsableAttribute class instructs the Web Parts infrastructure that the property has to be made available in the Web Part’s configuration panel. 

The PersonalizableAttribute class

The PersonalizableAttribute declares that the property can be personalized and defines the scope of the personalization. There 2 types of scopes:

1) Scope of type User, which means that the property can be personalized on a per-user basis.

2) Scope of type Shared, which means that the property personalization will be shared between all users.

Configurable WebPart Attributes
Following attributes enables the display of the custom properties in web part properties window.

1) [WebBrowsable(true)] - This will hide or show the property on the tool pane.

2) [Personalizable(PersonalizationScope.Shared)] - How the WebPart is configured, which can be per-user (PersonalizationScope.User), or for everyone (PersonalizationScope.Shared). 

3) [WebDescription("Description of List")] - Description for the property.

4) [WebDisplayName("My List Name")] - Label for the property.

5) [Category("Personalized Items")] - This will group your property according to category. If not declared, “Miscellaneous” will be used as the default.

6) [DefaultValue("Default")] - The default value for the property.

 Following are the steps for creating a Configurable Web Part Property :

1) Create two custom lists as follows:
i) "Products" with columns "Title", "Description" and "Price".

ii) "Customers" with columns "Title" and "Address".

2) Open Visual Studio and create a new Visual Web Part named MyVisualWP. In the "MyVisualWpUserControl.ascx" add a GridView control name "gvwProducts".

3) Open the solution in visual studio and modify the code in the Webpart file "MyVisualWP.cs" as follows. i) Add a configurable web part property named "ListName" using [WebBrowsable] attribute.
ii) Modify the CreateChildControls() to change the type of Control to Visual Web Part.

Following is source code for MyVisualWP.cs

Code Snippet

10. namespace VisualWebpartDemo.MyVisualWP
11. {
12.     [ToolboxItemAttribute(false)]
13.     public class MyVisualWP : WebPart
14.     {
15.  
16.         [WebBrowsable(true),
17.         Category("Personalize"),
18.         WebDisplayName("List Name"),
19.         WebDescription("Custom list name editable by user")]
20.         [Personalizable(PersonalizationScope.Shared)]
21.         public string ListName { get; set; }
22.  
23.         // Visual Studio might automatically update this path when you change the Visual Web Part project item.
24.         private const string _ascxPath =@"~/_CONTROLTEMPLATES/VisualWebpartDemo/MyVisualWP/MyVisualWPUserControl.ascx";
25.  
26.         protected override void CreateChildControls()
27.         {
28.             MyVisualWPUserControl control = Page.LoadControl(_ascxPath) asMyVisualWPUserControl;
29.             control.MyVisualWebpart = this;
30.             Controls.Add(control);
31.         }
32.     }
33. }

4) Now, go to the user control code behind file "MyVisualWPUserControl.ascx.cs" and modify code as highlighted below.
i) You will notice that we added a public property for getting the web part.
ii) Then we use the "ListName" property of the web part to specify the list name.
iii) We set the ViewFields property in the SPQuery object to display titles: Title", "Description", "Price"

and "Address".
Following is source code for MyVisualWPUserControl.ascx.cs

Code Snippet

7. namespace VisualWebpartDemo.MyVisualWP
8. {
9.     public partial class MyVisualWPUserControl : UserControl
10.     {
11.         public MyVisualWP MyVisualWebpart { get; set; }
12.         protected void Page_Load(object sender, EventArgs e)
13.         {
14.             if (MyVisualWebpart.ListName != null)
15.             {
16.                 SPSite oSite = SPContext.Current.Site;
17.                 using (SPWeb oWeb = oSite.OpenWeb())
18.                 {
19.                     SPQuery oQuery = new SPQuery();
20.                     oQuery.ViewFields = "<FieldRef Name='Title' /><FieldRef Name='Description' /><FieldRef Name='Price' /><FieldRef Name='Address' />";
21.                     oQuery.ViewFieldsOnly = true;
22.                     SPList oList = oWeb.Lists[MyVisualWebpart.ListName];
23.                     SPListItemCollection oColl = oList.GetItems(oQuery);
24.                     gvwProducts.DataSource = oColl.GetDataTable();
25.                     gvwProducts.DataBind();
26.                 }
27.             }
28.         }
29.     }
30. }

5) Deploy the solution and open the web part page in edit mode. 

6) Go to the web part properties and you can see the new custom property that we added.

7) Enter the list name "Products" and click "Apply" button, you will see the items in the Products List are populated in the GridView.

8) Now change the List Name to "Customers" and click "Apply" button. You will see the items in the Customers list will be populated in the GridView.

Note:- The above code defined property that requires the end user to configure the Web Part manually, typing the target list name autonomously and  made use of the standard behaviour of SharePoint and the out-of-the-box CustomPropertyToolPart.
But this is not a user-friendly and error-free approach. The right solution would probably be to provide a drop-down list with all the lists available in the current website, thereby avoiding typo errors and the consequent time consuming debugging tasks.
To customize the Web Parts’ configuration user interface you can create custom classes called "Editor Parts" which are controls hosted in a specific WebPartZone called EditorZone.