c# - LINQ 到 SQL : Selecting Name (string) by id (smallint)

Question

我需要检索一个 id 的名称(评估名称)

 public int GetAssessmentNo(int AssessmentNo)
        {
            int AssNo = (from a in contxt.View_Assessment
                         where a.id == AssessmentNo
                         select a.AssessmentName);
            return AssNo;
        }

无法将类型 System.Linq.IQueryable' 隐式转换为 int

Answer 1

您的查询返回一组整数。

使用其中之一:First()、Single()、FirstOrDefault()、SingleOrDefault()

public int GetAssessmentNo(int AssessmentNo)
{
    int AssNo = (from a in contxt.View_Assessment
                 where a.id == AssessmentNo
                 select a).Single().AssessmentName;
    return AssNo;
}

或:

public int GetAssessmentNo(int AssessmentNo)
{
    int AssNo = contxt.View_Assessment.Single(a => a.id == AssessmentNo).AssessmentName;
    return AssNo;
}