c# - 将 ObjectResult<int?> 转换为 List<int>

Question

我写了一个存储过程:-

CREATE PROCEDURE GET_USERSTORYDATA_EXISTS
    @MyWizardUserStoryId INT
   ,@ProjectId INT
   ,@StoryTitle NVARCHAR(MAX)
AS
BEGIN
    SET NOCOUNT ON;
    IF EXISTS (SELECT 1 FROM USERSTORY WHERE [MyWizardUserStoryId]=@MyWizardUserStoryId AND ProjectId=@ProjectId)
    BEGIN
        IF EXISTS (SELECT 1 FROM USERSTORY WHERE [MyWizardUserStoryId]=@MyWizardUserStoryId AND ProjectId=@ProjectId AND Title=@StoryTitle)
        BEGIN
            SELECT 0;
        END
        ELSE
         BEGIN
            SELECT 1;
        END
    END
    ELSE
         BEGIN
            SELECT 1;
        END

END
GO

我已经通过 Entity Framework 使用了这个过程:-

List<Int32>lst=context.GET_USERSTORYDATA_EXISTS(MyWizardUserStoryId,ProjectId,storyTitle);

但它给我错误:-

Can not implicitly convert type 'ObjectResult<int?>' to List<int>

Answer 1

自 ObjectResult<T> 工具 IEnumerable<T>你可以使用 ToList .但是，您还需要从可为空的 int 进行转换。最简单的方法是使用 Linq 进行投影 Select然后 ToList .此代码将用零替换任何空值:

List<Int32> lst = context
    .GET_USERSTORYDATA_EXISTS(MyWizardUserStoryId, ProjectId, storyTitle)
    .Select(i => i.GetValueOrDefault(0))
    .ToList();