插件页面赋值

在做服务插件开发时（日期计算），计算结束后的值，需要赋值给单据控件：
public class DataUtil : AbstractOperationServicePlugIn
{
public override void AfterExecuteOperationTransaction(Kingdee.BOS.Core.DynamicForm.PlugIn.Args.AfterExecuteOperationTransaction e)
{
base.AfterExecuteOperationTransaction(e);

// 服务操作后事件
DynamicObject regEntity = (from p in e.SelectedRows select p.DataEntity).ToArray()[0];
// 单据编号是否NULL
if (regEntity["F_DN_StartDate"] != null && regEntity["F_DN_EndDate"] != null)
{
DateTime startDate = Convert.ToDateTime(regEntity["F_DN_StartDate"].ToString());
DateTime endDate = Convert.ToDateTime(regEntity["F_DN_EndDate"].ToString());

TimeSpan leave = endDate.Subtract(startDate);

double leaveDate = Convert.ToDouble(leave.Days);

if (leave.Hours <= 4)
{
leaveDate += 0.5;
}

//this.View.Model.SetItemValueByID("F_DN_Leave_Day", leaveDate, -1);
}
}
}

但是页面没有View的定义，这里该如何给页面赋值呢？
急~