我如何在dbcontext.set中使用where条件< tentity>（） [英] How can I use where condition in dbcontext.set<tentity>()

问题描述

我想在MVC中使用Edit进行多项选择。所以我做了一个Jsonresult来获取该ID的数据： -



我尝试过的事情：

I want to use Edit in MVC for multiple selection . So I've made a Jsonresult to fetch the Data for that Id :-

What I have tried:

<pre>public JsonResult FetchDataForEdit()
        {
            int IDtoEdit = Convert.ToInt32(TempData["IDtoEdit"]);
            string MyTableName = Convert.ToString(TempData["MyTableName"]);
            
            try
            {
                Type tableType = typeof(CourseDesc);
                switch (MyTableName)
                {
                    case "CourseTbl":
                        tableType = typeof(CourseTbl);
                        break;
                    case "CourseDescTbl":
                        tableType = typeof(CourseDesc);
                        break;
                    case "CourseSubDesc":
                        tableType = typeof(CourseSubDesc);
                        break;
                    case "InternTbl":
                        tableType = typeof(InternShip);
                        break;
                    case "ContactTbl":
                        tableType = typeof(Contact);
                        break;
                }

                using (EBContext db = new EBContext())
                {
                    var results = new List<object>();
                    foreach (var item in db.Set(tableType))
                    {
                        //Want to Add result for selected IDtoEdit here
                        results.Add(item);
                    }

                    return new JsonResult { Data = results, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
                }

            }

            catch (Exception ex)
            {
                string innerMessage = (ex.InnerException != null) ? ex.InnerException.Message : "";
                return new JsonResult { Data = "Not Found", JsonRequestBehavior = JsonRequestBehavior.AllowGet };
            }

        }

推荐答案

假设 IDtoEdit 是实体的主键，你只想返回匹配的项目，使用查找：

Assuming the IDtoEdit is the primary key of the entity, and you only want to return the matching item, use Find:

using (var db = new EBContext())
{
    var results = new List<object>();
    var item = db.Set(tableType).Find(IDtoEdit);
    if (item != null) results.Add(item);
    
    return Json(results, JsonRequestBehavior.AllowGet);
}

DbSet.Find方法（Object []）（System.Data.Entity） [ ^ ]

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