Object reference not set to an instance of an object.大侠们帮忙了. 顶者有分

http://community.csdn.net/Expert/topic/5454/5454294.xml?temp=.5616876

Alarming server: Beijing occur error. Source: System.Data

Position: UniqueConstraint ==> Boolean IsConstraintViolated()

Message: Object reference not set to an instance of an object.

at System.Data.UniqueConstraint.IsConstraintViolated()

at System.Data.DataSet.EnableConstraints()

at System.Data.DataSet.set_EnforceConstraints(Boolean value)

at System.Data.DataTable.EndLoadData()

at Suzsoft.Alarming.DataAccess.ServerDataAccess.AddSendAlarming(SendAlarmingsRow dr)

at Suzsoft.Alarming.Service.SendEMail.OnExecute()

代码:

AlarmingDataSet.SendAlarmingsDataTable dt = ServerDataAccess.GetSendAlarmings();

AlarmingDataSet.SendAlarmingsRow dr = dt.NewSendAlarmingsRow();

dr.SendAlarmingId = Guid.NewGuid();

dr.RecordId = Mail.RecordId;