asp.net mvc 3 - Validation for textbox in MVC3 -

i need help. working mvc3-razor application. need validate textbox on view (.cshtml file) in such way that, starting 2 characters must "pr" , 4th character must "2". requirement. how achieve functionality? suggestions, great help. precious time.

model

public class registermodel {       public int id { get; set; }        [regularexpression(@"^pr[a-za-z0-9]2([a-za-z0-9]*)$", errormessage = "please enter valid name.")]       [required(errormessage = "name required.")]       public string name { get; set; } } 

view

@using (html.beginform("dymaniccontrollerpage", "test", formmethod.post, new { id = "frmindex" })) {        <div>           @html.labelfor(m => m.name)           @html.textboxfor(m => m.name)           @html.validationmessagefor(m => m.name)       </div> }