Silverlight-TimePicker control

Hi All,

Iam using Timepicker inside for Datagrid for CRM plugin app.

For my timepicker i have 15 minutes of time interval and format will be HH:MM eg:12:15AM

When i want to insert time manually for example 12:17 then it should automatically change to nearest value from timepicker like 12:30 or if it is 11:39AM then it will be 11:45AM.

Please some one give some idea to achieve the same.

Thanks in advance.....