Microsoft SharePoint 2007 Technologies

366 13.6 Connecting Web Parts

method that applies the changes made to the custom properties to the

Calendar control. The code is very straightforward; it basically sets the

Calendar control’s Show Day Header field to the value stored in the

MyShowDayHeader custom property and sets the Calendar control’s Show

Grid Lines field to the value stored in the

MyShowGridLines custom property.

From a development and testing perspective, it is sometimes useful to

set the

WebBrowsableAttribute to true to test the functionality of your cus-

tom properties before you implement the custom editor part. Once you are

happy that the custom properties are behaving as expected within your Web

Part, you can then reset

WebBrowsableAttribute to false. If you build the

solution at this stage with the

WebBrowsableAttribute set to true, the cus-

tom properties appear in the tool pane under the miscellaneous editor part,

and you can check and uncheck the property values accordingly (Figure

13.58). Opening and closing the browser will show you that the values per-

sist in the tool pane.

Step 2: Creating the custom editor part

Now that we have the appropriate functionality applied to our Web Part, all

that remains is to create the custom editor part. The creation of the custom

editor part is separated into two tasks. First, we need to create the class that

we will use for our custom editor part, and then we must override the

CreateEditorParts method in the main Web Part class. Figure 13.59

shows the code involved in creating the

EditorPart class that hosts our cus-

tom properties. Lines 16 through 28 instantiates and creates the two check-

box controls required for the editor part. Lines 30 through 36 override the

SyncChanges method; the SyncChanges method sets the initial values for

the properties in the editor part. Lines 38 through 44 override the

ApplyChanges method; the ApplyChanges method is self-explanatory in

that it applies the changes triggered from clicking the Apply or OK buttons

in the Web Part tool pane.

Figure 13.60 shows the code required to override the

CreateEditorParts method. This method should be inserted before the

RenderContents method of the sample code listed in Figure 13.57. The

CreateEditorParts method retrieves the collection of editor parts associ-

ated with the Web Part, and adds an additional editor part titled Calendar

Settings to the collection. Figure 13.61 shows the resultant output.

13.6 Connecting Web Parts

Web Parts themselves are excellent vehicles for providing users with relevant

information, but their true potential lies in their ability to communicate with

each other. A Web Part connection typically has a provider and a consumer.

13.6 Connecting Web Parts 367

Chapter 13

The provider Web Part initiates the communication by providing some form

of information that is of interest to a consumer Web Part. For example, let’s

suppose we have a simple form Web Part connected to a Shared Documents

Web Part on the home page of a team site. The form Web Part has the role of

the provider for the connection, so that when the user enters a name in the

form, the text is sent to the consumer Web Part, which in this scenario is the

Shared Documents Web Part. In the role of the consumer, the Shared Docu-

ments Web Part then consumes the name, and filters the Shared Documents

document library to display only those documents modified by the user that

match that name (Figure 13.62).

Figure 13.57

Creating custom

properties using C#.

368 13.6 Connecting Web Parts

Figure 13.58

Custom properties

with

WebBrowsable-

Attribute set to

true.

Figure 13.59

Creating Editor

Part Class (C#).

13.6 Connecting Web Parts 369

Chapter 13

When a Web Part is created, it does not automatically support connec-

tions; to provide this functionality, the Web Part itself has to implement a

number of interfaces, which we’ll cover shortly. You can determine whether

an existing Web Part supports connections by navigating to the Web Part

Figure 13.60

Overriding the

CreateEditorParts

method (C#).

Figure 13.61

Custom

Editor Part.

Figure 13.62

Form Web Part

filtering shared

documents

Web Part.

370 13.6 Connecting Web Parts

menu when in design mode. If the Connections menu is enabled, then the

Web Part supports connections. The actual type of connection that a Web

Part supports depends on a number of factors, including the type of Web

Part it is (i.e., whether it’s a server-side Web Part or a client-side Web Part),

the location of the Web Part (i.e., whether it is on the same Web Part page as

its connection Web Part), and whether it has exceeded the maximum num-

ber of connections permissible for the Web Part.

13.6.1 Connection Interfaces

The Web Part Framework that came with Windows SharePoint Services

2.0 and SharePoint Portal Server 2003 provided a standard set of connec-

Figure 13.63

SendUrl

IWebPartField

provider Web Part.