In all most of the time, people are using the famous Control "DropDownList" to put a collection of data. But, what happen when this list is so huge and may a performance issue for loading your page? Even if you do that, you are killing your End-Users by scrolling in a long list. It's not a good idea for your Users. So, what we can do? The "Dialog Picker" will be your help.
I think, you will already experience with it when you try looking for Users, Groups, Audiences,... To provide its own in SharePoint 2007 is very simple, it provides you all the needed base classes which you need to inherit from. Let's start implementing step by step each control.
Step 1: Editor
Build a class that inherits from "Microsoft.SharePoint.WebControls.EntityEditorWithPicker". After that you have to provide the type of the dialog (step 2) in the "PickerDialogType" property. Then, provides the separator char in the "EntitySeparator" property.
See below the Editor:
Step 2: Dialog
Build a class that inherits from "Microsoft.SharePoint.WebControls.PickerDialog". This base class is responsible to provide results that matches with the entered text provided in the search input.
See below the dialog:
The base class constructor has 3 parameters:
- Query (Step 3) contains the logic for retrieving data
- A Control that display the result set
- An instance of the Editor (Step 1)
Step 3: Query
Build a class that inherits from "Microsoft.SharePoint.WebControls.SimpleQueryControl". In this class, you have to override the method "IssueQuey" which will contains the logic for retrieving Data, it must be in a "System.Data.DataTable". And sets it to the PickerDialog's Results property. Don't forget to return the row count. Otherwise, no result are displayed.
In addition, override the method "GetEntity" that has a "System.Data.DataRow" parameter. This Row is a DataTable you have provided before. The goal is this method in to Strongly Typed your result with the "Microsoft.SharePoint.WebControls.PickerEntity" object. Which you can specify a Key, DisplayText. Then, the "IsResolved" property to true. This ensures that the provided entity is correct.
See blow the output of the Dialog (Step 2) that populates data corresponding to the entered input text:
When click on the OK button, the editor will receive the Entity value separated by the specified "EntitySeparator" if there is more than one Entity.
See the final result in the Picker Editor:
Hope it helps.