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 object

CrmServiceClient svc = new CrmServiceClient(

new System.Net.NetworkCredential("username", "password", "domain"),

                "crmhost",

                "443",

                "crmorganization",

                false,

                true

                );

// check the connection to CRM was successful

if (!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 entity

Dictionary<string, CrmDataTypeWrapper> attributes = new Dictionary<string, CrmDataTypeWrapper>();

//this doesn't work

attributes.Add("new_somedatefield", null);

// and this doesn't work

attributes.Add("new_somedatefield", new CrmDataTypeWrapper(null, CrmFieldType.CrmDateTime));

// this also doesn't work

DateTime? 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。