entity-framework

问题 The Issue... As the title states, I've installed the .NET Core 2.1 SDK and created a new .NET Core 2.1 project. When I go to Project > Add Item... > Data , I do not have the ADO.NET Entity Data Model option. I am using Visual Studio 2017 15.7.3 , which I've installed only hours ago. The Error and Warning logs are clean. Any assistance is appreciated. What I've done so far... Researched. You'll notice I've pulled most of my attempts to solve this issue from primarily these three resources:

问题 The Issue... As the title states, I've installed the .NET Core 2.1 SDK and created a new .NET Core 2.1 project. When I go to Project > Add Item... > Data , I do not have the ADO.NET Entity Data Model option. I am using Visual Studio 2017 15.7.3 , which I've installed only hours ago. The Error and Warning logs are clean. Any assistance is appreciated. What I've done so far... Researched. You'll notice I've pulled most of my attempts to solve this issue from primarily these three resources:

问题 I have two tables: CREATE TABLE Thing ( Id int, Name nvarchar(max) ); CREATE TABLE SubThing ( Id int, Name nvarchar(max), ThingId int (foreign key) ); I want to select all Things with a listing of SubThings and set them to a ThingViewModel. The Thing ViewModel is simple: public class ThingViewModel { public int Id { get; set; } public string Name { get; set; } public List<SubThingViewModel> SubThings { get; set; } } The SubThingViewModel is: public class SubThingViewModel { public int Id {

问题 My DBA says that there are way too many connection open and he thinks it is my code in .net that is leaving them open. I am using LINQ querys and EF code first. Example Method: public List<Stuff> GetStuff() { var db = new DBContext(); var results = db.stuff.toList(); return results; } Do I need to dispose the db var once I am done? My understanding is that I didn't need to in EF and LINQ. Please point me to a Microsoft documentation about managing connection in code or best practices for LINQ

问题 I am struggling with what seemed to be a couple of basic operations. Let's say I've got a class named Master: public class Master { public Master() { Children = new List<Child>(); } public int Id { get; set; } public string SomeProperty { get; set; } [ForeignKey("SuperMasterId")] public SuperMaster SuperMaster { get; set; } public int SuperMasterId { get; set; } public ICollection<Child> Children { get; set; } } public class Child { public int Id { get; set; } public string SomeDescription {

问题 I'm still shaky with my use of ajax so there are a couple holes in my implementation here. I am trying to post to a controller action that will call a stored procedure to update my view model and then reload the div that will display the information. Ajax Post: $("#order-summary-panel").click(function(){ $.ajax({ url: '@Url.Action("GetOrderSummary", "Home")', type: 'POST', success: function() { alert("It Worked!") } }); }); Controller Action: [HttpPost] public ActionResult GetOrderSummary {

问题 I'm still shaky with my use of ajax so there are a couple holes in my implementation here. I am trying to post to a controller action that will call a stored procedure to update my view model and then reload the div that will display the information. Ajax Post: $("#order-summary-panel").click(function(){ $.ajax({ url: '@Url.Action("GetOrderSummary", "Home")', type: 'POST', success: function() { alert("It Worked!") } }); }); Controller Action: [HttpPost] public ActionResult GetOrderSummary {

问题 I have a SQLite table that contains every test result we've run, and I'm looking to write an entity framework query that returns only the most recent test result per project. Normally, I'd assume this would be "group by project id, return row with the max updated value," or, alternatively, "sort by date and return first". However, when I try the query, I keep getting Entity Framework "could not be translated" errors. Here's what I've tried: results = await _context.Results .Include(x => x

问题 I have a SQLite table that contains every test result we've run, and I'm looking to write an entity framework query that returns only the most recent test result per project. Normally, I'd assume this would be "group by project id, return row with the max updated value," or, alternatively, "sort by date and return first". However, when I try the query, I keep getting Entity Framework "could not be translated" errors. Here's what I've tried: results = await _context.Results .Include(x => x

问题 I am trying to describe a many-to-many self-referential relationship to Entity Framework Core 2. Essentially what I'm trying to model is a sort of tree structure, in which each element can have an arbitrary number of parent and child elements (so I guess more a graph than a tree). Here's what I have so far: public class OrgLevel { ... public ICollection<OrgLevelOrgLevels> OrgLevelOrgLevelsAsParent { get; set; } public ICollection<OrgLevelOrgLevels> OrgLevelOrgLevelsAsChild { get; set; }