你好，我有想過用union可是最後卻失敗，然後用您的方法有出現錯誤
The type 'Tmht.HD.Patients.Models.DrPatDto' appears in two structurally incompatible initializations within a single LINQ to Entities query. A type can be initialized in two places in the same query, but only if the same properties are set in both places and those properties are set in the same order.

這是我目前的程式碼

 public List<DrPatDto> FindOpdDrPat(string cid, string Pat_Guid, DateTime Opdate)
        {

            var query = (from x in _repo.PAT_SCHEDULE
                         join b in _repo.PATIENT
                         on x.PAT_GUID equals b.GUID
                         where (x.CID == cid && x.PAT_GUID == Pat_Guid && x.PAT_SOURCE == "OPD" && x.DIA_DATE == Opdate || x.DIA_DATE == new DateTime(1900, 1, 1))
                         select new DrPatDto
                         {

                             PAT_SOURCE = x.PAT_SOURCE,
                             BedNO = x.BED_NO,
                             PAT_NAME = b.PAT_NAME,
                             PAT_NO = b.PAT_NO,
                             OPDDate = x.DIA_DATE,
                         }).OrderByDescending(x => x.OPDDate);

            var query2 = (from x in _repo.PAT_SCHEDULE
                          join c in _repo.HD_REQUIRE
                          on x.PAT_GUID equals c.PAT_GUID
                          where (x.CID == cid && x.PAT_GUID == Pat_Guid && x.DIA_DATE == Opdate || x.DIA_DATE == new DateTime(1900, 1, 1))
                          select new DrPatDto
                          {                              
                             
                              IPD_PAT_SOURCE = c.PAT_SOURCE,
                              IpdBedNo = c.IPD_BED_NO,
                              OPDDate = x.DIA_DATE,
                          }).OrderByDescending(x => x.OPDDate);
            foreach (DrPatDto dto2 in query2)
            {
                dto2.PAT_NAME = _repo.PATIENT.Where(x => x.CID == dto2.CID && x.GUID == dto2.PAT_GUID).FirstOrDefault<PATIENT>().PAT_NAME;
                dto2.PAT_NO = _repo.PATIENT.Where(x => x.CID == dto2.CID && x.GUID == dto2.PAT_GUID).FirstOrDefault<PATIENT>().PAT_NO;
            }                                 
            var unionResult = query.Union(query2).ToList<DrPatDto>();
            return unionResult;
           
        }

請問這問題可能是哪一種?

tenno081
你要先搞懂ToList()這個方法
他是把資料拉出來的動作
所以你在用之前資料並沒被查詢出來
所以你的foreah不能使用....
要把合併的結果拉到foreach之前
然後改成讀取UNION的結果

var unionResult = query.Union(query2).ToList<DrPatDto>();
            
foreach (DrPatDto dto2 in unionResult)
{
    dto2.PAT_NAME = _repo.PATIENT.Where(x => x.CID == dto2.CID && x.GUID == dto2.PAT_GUID).FirstOrDefault<PATIENT>().PAT_NAME;

    dto2.PAT_NO = _repo.PATIENT.Where(x => x.CID == dto2.CID && x.GUID == dto2.PAT_GUID).FirstOrDefault<PATIENT>().PAT_NO;
}                                 

不好意思，是我的疏忽，但是我就算沒用foreach迴圈他還是有一樣的錯誤，我照著您的方法再修改後結果還是不變@@

tenno081

but only if the same properties are set in both places and those properties are set in the same order.

好像說做了一樣排序
你把ORDER拉下來試試
先Union在ORDER看看

結果還是不變，不好意思，我可能打算先這樣做

 var query3 = (from a in query
                          join b in query2
                          on a.PAT_GUID
                          equals b.PAT_GUID                         
                          select new DrPatDto
                          {
                              PAT_SOURCE = a.PAT_SOURCE,
                              IPD_PAT_SOURCE = b.IPD_PAT_SOURCE,
                              BedNO = a.BedNO,
                              IpdBedNo = b.IpdBedNo,
                              PAT_NAME = a.PAT_NAME,

                          }).ToList<DrPatDto>();
            return query3;

雖然沒查到，但想請問這個做法有用嗎?

阿，真是感謝，我後來是這樣做

List<DrPatDto> dto = query.Union(query2).ToList<DrPatDto>();

結果這樣就可以了@@