Question

当我尝试执行this reply中的最后一行时，我收到错误。我运行以下代码：

QueryExpression query = new QueryExpression
{
  LogicalName = "contact",
  ...
}

BusinessEntityCollection response = ServiceProxy.RetrieveMultiple(query);
Logify("count: " + response.BusinessEntities.Count);
BusinessEntity piff= response.BusinessEntities.First();
Logify("piff: " + (piff != null));

DynamicEntity poof = response.BusinessEntities.First() as DynamicEntity;
Logify("poof: " + (poof != null));

计数为1，因此正确执行调用并产生一些效果。根据日志， piff 不是null，所以它包含一些东西。但是，在转换之后（为了访问实体的字段是必需的），我将它变为 null （或者在尝试显式时我得到异常投了shabang）。

例外是：

无法转换类型＆＃39; Microsoft.Crm.SdkTypeProxy.contact＆＃39;输入＆＃39; Microsoft.Crm.Sdk.DynamicEntity＆＃39;。

怎么办？！

Answer 1

答案是使用RetrieveMultipleRequest。重写代码：

QueryExpression query = new QueryExpression
{
    LogicalName = "contact",
    ...
}

RetrieveMultipleRequest rmr = new RetrieveMultipleRequest()
{
    Query = query,
    ReturnDynamicEntities = true
};

RetrieveMultipleResponse rmrresp = ServiceProxy.Execute(rmr) as RetrieveMultipleResponse;
BusinessEntityCollection response = rmrresp.BusinessEntityCollection;
Logify("count: " + response.BusinessEntities.Count);
BusinessEntity piff= response.BusinessEntities.First();
Logify("piff: " + (piff != null));

DynamicEntity poof = response.BusinessEntities.First() as DynamicEntity;
Logify("poof: " + (poof != null));

无法转换或将BusinessEntity转换为DynamicEntity

1 个答案: