Updating Related Data with the Entity Framework in an ASP.NET MVC Application (6 of 10)http://asp.netMon, 18 Jul 2011 16:29:27 GMTumbracoComments for Updating Related Data with the Entity Framework in an ASP.NET MVC Application (6 of 10)enComment Posted by airmarohttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationWed, 20 Apr 2011 16:29:15 GMT00000000-0000-0000-0000000012890The code block below the following paragraph should have @Html.LabelFor(model => model.Courses) instead of @Html.LabelFor(model => model.OfficeAssignment.Location)

In Views\Instructor\Edit.cshtml, add a Courses field with an array of check boxes by adding the following code immediately after the div elements for the OfficeAssignment field:

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationWed, 20 Apr 2011 17:54:04 GMT00000000-0000-0000-0000000012893Thanks for the note -- the courses field is created by the following div elements and this div element is not needed in the code block as it should already exist in the view, so I've removed it.

]]>Comment Posted by fredbear7232http://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationMon, 16 May 2011 10:43:07 GMT00000000-0000-0000-0000000013185for some reason when I'm going thru the tutorial and I try to use the edit code provided, I keep getting this exception: A first chance exception of type 'System.Data.Entity.Infrastructure.DbUpdateConcurrencyException' occurred in EntityFramework.DLL.

Maybe I should go thru the concurrency tut before I post this? :) But it seems wierd because it's ONLY the edit page. the creat/delete pages work just fine. Any thoughts?

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSun, 22 May 2011 11:08:37 GMT00000000-0000-0000-0000000013242@ fredbear7232 - I haven't seen that exception. My first thought is to make sure you have the latest EF 4.1 (not an earlier CTP or RC). You might also download the sample project and see if you get the error there to determine whether there's something about your machine setup. There is an EF bug in concurrency-related code that is related to machine setup, and this could also be another manifestation of that issue.

]]>Comment Posted by kingabhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSun, 29 May 2011 01:15:06 GMT00000000-0000-0000-0000000013306I found that when adding the code to display the CourseID in Views\Course\Edit.cshtml, I had to use an EditorFor field instead of a DisplayFor field. Otherwise it errored out when trying to save changes to a course, such as adjusting the number of credits.

]]>Comment Posted by kingabhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSun, 29 May 2011 01:16:41 GMT00000000-0000-0000-0000000013307P.S. - Great tutorial!

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationTue, 31 May 2011 11:59:18 GMT00000000-0000-0000-0000000013341@kingab - I am not able to reproduce that error -- I have no trouble saving changes in the Course Edit page with the DisplayFor field being used for the CourseID. Can you provide more information about the error you were getting?

]]>Comment Posted by gorthonhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 04 Jun 2011 16:04:16 GMT00000000-0000-0000-0000000013408I also found that when adding the code to display the CourseID in Views\Course\Edit.cshtml, I had to use an EditorFor field instead of a DisplayFor field. If I don't the "Unable to save changes" message shows and the course number shows 0. I commented out the try catch and I get an DBUpdateConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries. I pasted over with the code from the example and still get the same error.

]]>Comment Posted by mherdotinfohttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSun, 05 Jun 2011 16:18:26 GMT00000000-0000-0000-0000000013412I confirm the error Kingab and gorthon mentioned.

]]>Comment Posted by mherdotinfohttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSun, 05 Jun 2011 16:18:42 GMT00000000-0000-0000-0000000013413good tutorial

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationTue, 07 Jun 2011 18:06:32 GMT00000000-0000-0000-0000000013445@kingab, gorthom, or mherdotinfo - Do you get this error if you download the application from Code Gallery (that project uses the DisplayFor helper)?

]]>Comment Posted by gary7101http://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 25 Jun 2011 14:55:53 GMT00000000-0000-0000-0000000013613When adding the code block for the check box array, (Views\Instructor\Edit.cshtml) the html does not validate and cannot compile. I get intellisense errors on the table row tags. I've directly copied the code from this page, as well manually entered, but it will not validate. Error on the tr tag says text is not allowed between the opening and closing tag.

]]>Comment Posted by gary7101http://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 25 Jun 2011 15:32:23 GMT00000000-0000-0000-0000000013615My apologies for this question: Why is the downloadable source code not the same as the tutorial?

]]>Comment Posted by gary7101http://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 25 Jun 2011 15:35:37 GMT00000000-0000-0000-0000000013616Sorry, please disregard my last post. I found the correct download.

]]>Comment Posted by gary7101http://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 25 Jun 2011 16:00:04 GMT00000000-0000-0000-0000000013617In regards to my first post related to tag errors; I've resolved the compiler error which was due to an omitted line of code in the InstructorController code. However, the table row tags continue to cause intellisense to claim errors. This does not seem to be a problem in running the project, but is annoying when working in the editor!

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationMon, 04 Jul 2011 14:36:00 GMT00000000-0000-0000-0000000013684@gary7101 - Sorry, the download link is incorrect and I've been trying to get it fixed but it hasn't happened yet. If you can send a screen shot of your IntelliSense error to me (tdykstra at microsoft dot com) I'll look into it.

]]>Comment Posted by Drawerhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationTue, 05 Jul 2011 14:50:58 GMT00000000-0000-0000-0000000013700I'm using MS SQL Server 2008. When I tried to delete an instructor I got the error: The DELETE statement conflicted with the REFERENCE constraint "Department_Administrator". The conflict occurred in database "MvcContosoUniversity", table "dbo.Department", column 'PersonID'.

The statement has been terminated.

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationWed, 06 Jul 2011 17:29:39 GMT00000000-0000-0000-0000000013706@Drawer - That error means you assigned a instructor as administrator of a department and then tried to delete the instructor. You will have to assign a different instructor to the department first, then you can delete the instructor.

]]>Comment Posted by Drawerhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationThu, 07 Jul 2011 03:42:21 GMT00000000-0000-0000-0000000013709Thanks, tdykstra. I understand the error, but I don't know how to fix it. Demaprtment.PersonID can be null, so I thought EF would automatically create a Delete Rule = "Set Null" for the "Department_Administrator" constraint, but it didn't. How to set Update/Delete rules in context OnModelCreating method?

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationFri, 08 Jul 2011 20:55:33 GMT00000000-0000-0000-0000000013734@Drawer - See this StackOverflow question: stackoverflow.com/

]]>Comment Posted by Drawerhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationSat, 09 Jul 2011 05:30:12 GMT00000000-0000-0000-0000000013736@tdykstra - thank you!

]]>Comment Posted by czechdudehttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationThu, 14 Jul 2011 07:39:01 GMT00000000-0000-0000-0000000013760the link to download the application leads to web forms version!

]]>Comment Posted by mrbelkhttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationThu, 14 Jul 2011 15:55:25 GMT00000000-0000-0000-0000000013761Why doesn't the date format validation on the hire date work? Also, how come we can't use "ModelState.IsValid" in the HTTP POST Edit method?

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationMon, 18 Jul 2011 15:06:22 GMT00000000-0000-0000-0000000013779@mrbelk - This is a bug in the code which I will fix in the tutorial. Add ", Instructor instructor" to the end of the parameter list for the Edit method, and then enclose the try/catch block in an "If (ModelState.IsValid)" statement.

]]>Comment Posted by tdykstrahttp://asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/updating-related-data-with-the-entity-framework-in-an-asp-net-mvc-applicationMon, 18 Jul 2011 16:29:27 GMT00000000-0000-0000-0000000013781@mrbelk - Or a better solution: don't add an Instructor parameter to the method signature, just wrap the try/catch block in

if (TryUpdateModel(instructorToUpdate, "", null, new string[] { "Courses" }))

And omit the UpdateModel from inside the try/catch block.

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