c# - DbEntityValidationException When Inserting Record -

sorry long post. have these table relationships:

- room has many-to-many relationship activity - roomactivity has one-to-many relationship room , activity - item has many-to-many relationship part - itempart has one-to-many relationship item , part - stage has foreign key relationship roomactivity , itempart - submission has foreign key relationship stage 

i have web application employees can submit today, consist of room, activity, item, part submit form.

my controller:

public actionresult create() {   viewbag.activityrejectcodeid = getrejectcodesbyactivity(0);   viewbag.activities = getactivities();   viewbag.workstations = getrooms();   viewbag.platforms = getitems();   viewbag.parts = getparts();   return view(); }  [httppost] [validateantiforgerytoken] public actionresult create(workordersubmission workordersubmission) {   if (modelstate.isvalid)   {     var activityid = int32.parse(request.form["stage.roomactivity.activity.id"]);     var workstationid = int32.parse(request.form["stage.roomactivity.workstation.id"]);     var platformid = int32.parse(request.form["stage.itempart.platform.id"]);     var partid = int32.parse(request.form["stage.itempart.part.id"]);      var rs = (from ps in db.stages       join wa in db.roomactivities on ps.roomactivityid equals wa.id       join pp in db.itemparts on ps.itempartid equals pp.id       ps.roomactivity.activityid == activityid          && ps.roomactivity.roomid == workstationid          && ps.itempart.itemid == platformid          && ps.itempart.itemid == partid       select new { ps.id }).firstordefault();      var stageid = rs.id;      workordersubmission.stageid = stageid;     workordersubmission.submissiondate = datetime.now;      // error when saving here     db.workordersubmissions.add(workordersubmission);     db.savechanges();      return redirecttoaction("index");   }    viewbag.stageid = new selectlist(db.stages.orderby(p => p.name), "id", "name", workordersubmission.stageid);   return view(workordersubmission); }  public selectlist getactivities() {   var results = (from ps in db.stages   join wa in db.roomactivities on ps.roomactivityid equals wa.id   join in db.activities on wa.activityid equals a.id   select new   {     id = wa.activityid,     name = a.name   })   .distinct()   .orderby(n => n.name);    return new selectlist(results, "id", "name"); } 

my view:

<div class="editor-label">   @html.labelfor(model => model.stage.roomactivity.activity.id, "activity") </div> <div class="editor-field">   @html.dropdownlistfor(model => model.stage.roomactivity.activity.id,     (selectlist)viewbag.activities, "")   @html.validationmessagefor(model => model.stage.roomactivity.activity.id) </div> 

i'm getting error below(updated):

validation failed entity [part]. validation errors: number: number field required.  validation failed entity [item]. validation errors: name: name field required.  validation failed entity [activity]. validation errors: name: name field required.  validation failed entity [room]. validation errors: name: name field required 

why error on part, item, activity, room? i'm trying insert new submission.

stage model:

public partial class stage {     public stage()     {         this.workordersubmissions = new hashset<workordersubmission>();     }      public int id { get; set; }     public int roomactivityid { get; set; }     public int itempartid { get; set; }     public string description { get; set; }     public string name { get; set; }      public virtual itempart itempart { get; set; }     public virtual roomactivity roomactivity { get; set; }     public virtual icollection<workordersubmission> workordersubmissions { get; set; } } 

workordersubmission model:

public partial class workordersubmission {     public int id { get; set; }     public int workorderid { get; set; }     public int stageid { get; set; }     public system.datetime submissiondate { get; set; }      public virtual stage stage { get; set; }     public virtual workorder workorder { get; set; } } 

could add code more information dbentityvalidationexception , show it?

try {     db.savechanges(); } catch (dbentityvalidationexception e) {     string errorformat = @"validation failed entity [{0}]. validation errors:" + environment.newline + @"{1}";     var errorlist = new list<string>();     foreach (var entityvalidationerror in e.entityvalidationerrors)     {         var entityname = entityvalidationerror.entry.entity.gettype().name;         var errors = string.join(environment.newline, entityvalidationerror.validationerrors.select(a => a.propertyname + ": " + a.errormessage));         errorlist.add(string.format(errorformat, entityname, errors));     }     throw new exception(string.join(environment.newline + environment.newline, errorlist) + environment.newline, e); }