1.Microsoft.Xrm.Sdk必须是9.0版本或者更高

2.多选项集字段，单个选项数据过滤，示例如下：

queryExpression.Criteria.AddCondition("字段名称", ConditionOperator.ContainValues, 100000003);

3.多选项集字段数据过滤，示例如下：

int[] hikingValue = new int[] { 100000000, 100000001 };
ConditionExpression condition = new ConditionExpression("字段名称", ConditionOperator.ContainValues, hikingValue);

FilterExpression filter = new FilterExpression();            
filter.AddCondition(condition);

queryExpression.Criteria.AddFilter(filter);

_serviceProxy.RetrieveMultiple(queryExpression);

4.多选项集字段，获取字段信息，示例如下：

// 显示名称
item.FormattedValues["字段名称"];
// 字段值，sc为 OptionSetValue集合，遍历即可拿到value
OptionSetValueCollection sc = item.GetAttributeValue<OptionSetValueCollection>("字段名称");              

5.多选项集字段赋值，示例如下：

OptionSetValueCollection activities = new OptionSetValueCollection();
activities.Add(new OptionSetValue(1)); 
activities.Add(new OptionSetValue(9));
newEntity["字段名称"] = activities;

_serviceProxy.Create(newEntity);