.net - 二元运算符 LessThan 没有为类型 'System.Nullable` 1[System.DateTime ]' and ' System.Nullable`1[System.DateTimeOffset]' 定义

Question

我正在尝试创建 Odata 端点，但每当我尝试执行任何涉及日期的查询时都会收到此错误。

我在下面的非常简单示例中重新创建了它。

数据库表

EDMX(片段)

<edmx:ConceptualModels>
  <Schema Namespace="DataWarehouseModel" Alias="Self" annotation:UseStrongSpatialTypes="false" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns="http://schemas.microsoft.com/ado/2009/11/edm">
    <EntityContainer Name="DataWarehouseEntities1" annotation:LazyLoadingEnabled="true">
      <EntitySet Name="People" EntityType="DataWarehouseModel.Person" />
    </EntityContainer>
    <EntityType Name="Person">
      <Key>
        <PropertyRef Name="ID" />
      </Key>
      <Property Name="ID" Type="Int32" Nullable="false" annotation:StoreGeneratedPattern="Identity" />
      <Property Name="FirstName" Type="String" Nullable="false" MaxLength="50" FixedLength="false" Unicode="true" />
      <Property Name="LastName" Type="String" Nullable="false" MaxLength="50" FixedLength="false" Unicode="true" />
      <Property Name="DOB" Type="DateTime" Nullable="false" Precision="3" />
    </EntityType>
  </Schema>
</edmx:ConceptualModels>
<!-- C-S mapping content -->
<edmx:Mappings>
  <Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2009/11/mapping/cs">
    <EntityContainerMapping StorageEntityContainer="DataWarehouseModelStoreContainer" CdmEntityContainer="DataWarehouseEntities1">
      <EntitySetMapping Name="People">
        <EntityTypeMapping TypeName="DataWarehouseModel.Person">
          <MappingFragment StoreEntitySet="Person">
            <ScalarProperty Name="DOB" ColumnName="DOB" />
            <ScalarProperty Name="LastName" ColumnName="LastName" />
            <ScalarProperty Name="FirstName" ColumnName="FirstName" />
            <ScalarProperty Name="ID" ColumnName="ID" />
          </MappingFragment>
        </EntityTypeMapping>
      </EntitySetMapping>
    </EntityContainerMapping>
  </Mapping>
</edmx:Mappings>

型号

public partial class Person
{
    [Key]public int ID { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public System.DateTime DOB { get; set; }
}

Controller

public class PersonController : ODataController
{
    private DataWarehouseServiceContext db = new DataWarehouseServiceContext();

    private bool PersonExists(int key)
    {
        return db.Persons.Any(p => p.ID == key);
    }

    [EnableQuery]
    public IQueryable<Person> Get()
    {
        return db.Persons;
    }

    protected override void Dispose(bool disposing)
    {
        db.Dispose();
        base.Dispose(disposing);
    }
}

查询

http://localhost:53205/OData/Person?$top=20&$filter=DOB eq 1972-11-20T00:00:00.000Z
http://localhost:53205/OData/Person?$top=20&$filter=DOB lt 1972-11-20T00:00:00.000Z

等等

所有失败并显示以下行的消息:-

The query specified in the URI is not valid. The binary operator LessThan is not defined for the types 'System.Nullable`1[System.DateTime]' and 'System.Nullable`1[System.DateTimeOffset]'.

有人能帮忙吗？

Answer 1

这里的问题是，虽然 Microsoft 有 partly添加了 DateTime 支持(see comments)，OData V4 不包括 DateTime 作为原始类型。这意味着您的过滤器仍然需要使用 DateTimeOffset。

虽然不理想，但将 DateTime 转换为 DateTimeOffset 似乎可以解决问题。

/OData/Person?$top=20&$filter=cast(DOB,'Edm.DateTimeOffset') eq 1972-11-20T00:00:00.000Z