如何使用 CrmServiceClient 设置空属性值

Question

我正在努力使用 CrmServiceClient 将属性值更新为 null。我的代码对于非空值工作正常，但因异常而失败：你调用的对象是空的。在 Microsoft.Xrm.Tooling.Connector.CrmServiceClient.AddValueToPropertyList(KeyValuePair 2  Field, AttributeCollection PropertyList)      at  Microsoft.Xrm.Tooling.Connector.CrmServiceClient.UpdateEntity(String  entityName, String keyFieldName, Guid id, Dictionary2 fieldList, String applyToSolution, Boolean enabledDuplicateDetection, Guid batchId)每当我尝试设置空值时。到目前为止，我已经尝试了以下方法：// create Crm service client objectCrmServiceClient svc = new CrmServiceClient(new System.Net.NetworkCredential("username", "password", "domain"),                "crmhost",                "443",                "crmorganization",                false,                true                );// check the connection to CRM was successfulif (!svc.IsReady){    throw new Exception("Could not connect to CRM Organization.", svc.LastCrmException);}// create a Dictionary to store the attributes to be added to the entityDictionary<string, CrmDataTypeWrapper> attributes = new Dictionary<string, CrmDataTypeWrapper>();//this doesn't workattributes.Add("new_somedatefield", null);// and this doesn't workattributes.Add("new_somedatefield", new CrmDataTypeWrapper(null, CrmFieldType.CrmDateTime));// this also doesn't workDateTime? nullDate = new DateTime();nullDate = null;attributes.Add("new_somedatefield", new CrmDataTypeWrapper(nullDate, CrmFieldType.CrmDateTime));svc.UpdateEntity("new_entityname", "new_entitynameid", (Guid)data[metaData.PrimaryIdAttribute], attributes));文档中没有特别提到设置空值。有没有人成功地实现了这一目标？编辑 - 为了澄清我需要针对 Dynamics CRM 2015，CrmServiceClient 上的 Update 方法直到 2016 年才可用。