Question

我通过继承ODataEntityTypeSerializer实现了自定义序列化程序。序列化程序设置＆＃34; MessageStateName＆＃34;的值。通过从＆＃34; MessageState＆＃34;的值获取BayStateEnum的名称。除非URL包含＆＃34; $ select＆＃34;，否则它只能正常工作。我调试了代码并发现它已被执行且entityInstanceContext.EntityInstance具有正确的值，但是SystemInstanceContext.EdmModel，类型为System.Web.OData.Query.Expressions.SelectExpandBinder.SelectSome，仍然有一个空的＆＃34; MessageStateName＆＃34;

public class CustomEntitySerializer : ODataEntityTypeSerializer
{
    public CustomEntitySerializer(ODataSerializerProvider serializerProvider)
        : base(serializerProvider)
    {
    }
    public override ODataEntry CreateEntry(SelectExpandNode selectExpandNode, EntityInstanceContext entityInstanceContext)
    {
        if (entityInstanceContext.EntityInstance is SmartLinkInfoModel)
        {
            var smartLinkInfo = entityInstanceContext.EntityInstance as SmartLinkInfoModel;
            if (smartLinkInfo.ModemIMEI != null)
            {
                smartLinkInfo.ModemIMEIString = "0x" + string.Join(string.Empty, smartLinkInfo.ModemIMEI.Select(b => (b - 48).ToString()));
            }
            if (smartLinkInfo.SmartLinkHardwareId != null)
            {
                smartLinkInfo.SmartLinkHardwareIdString = "0x" + string.Join(string.Empty, smartLinkInfo.SmartLinkHardwareId.Select(b => b.ToString()));
            }
            if (smartLinkInfo.XbeeSourceId != null)
            {
                smartLinkInfo.XbeeSourceIdString = "0x" + string.Join(string.Empty, smartLinkInfo.XbeeSourceId.Select(b => b.ToString()));
            }
        }
        else if (entityInstanceContext.EntityInstance is BayMessageModel)
        {
            var bayMessage = entityInstanceContext.EntityInstance as BayMessageModel;
            bayMessage.MessageStateName = Enum.GetName(typeof(BayStateEnum), bayMessage.MessageState);
        }
        return base.CreateEntry(selectExpandNode, entityInstanceContext);
    }
}

Answer 1

你的代码改变了entityInstanceContext.EntityInstance是对的，但它不会改变select的结果，你可以看到

object propertyValue = entityInstanceContext.GetPropertyValue(structuralProperty.Name);

在ODataEntityTypeSerializer的{{1}}方法中，如果CreateStructuralProperty为structuralProperty.Name，则应覆盖此方法，然后使用MessageStateName

当URL包含$ select时，自定义序列化程序在oData 4的Web API 2中不起作用

1 个答案: