CreateUserWizard如何获取定制控件？
DropDownList RoleSelect = (DropDownList)CreateUserWizard1.CreateUserStep.FindControl( "Role ");
报未将对象的引用设置到对象的实例

[解决办法]
DropDownList RoleSelect = (DropDownList)CreateUserWizard1.CreateUserStep.ContentTemplateContainer.FindControl( "Role ");