sql server - Entity Framework 6 query generates NullReferenceException -


edit: not problem ignorance of basic programming (such trying dereference null object reference).

edit: added stack trace ef within linqpad.

using ef6, have simple query :

var menu = dbcontext.tree.where(t => t.left > 2 && t.right < 10).tolist();

this worked right until mysteriously stopped. dbcontext.tree view in sql server 2012. using linqpad5, results expect using built-in connection. setting ef connection project, nre. checking sql, can copy , paste sql query window , proper results. nre without call, also.

i've tried updating model database refresh anything. i've tried removing view model , updating. i've tried deleting model entirely , recreating it. i've restarted visual studio , computer. same nre query. don't know else can try, , nre makes no sense me @ all, given results expect using ef. i'd chalk bug ef if didn't see working previously.

has dealt this? searching online specific set of circumstances has produced nothing.

stack trace :

at system.data.entity.core.entitykey.addhashvalue(int32 hashcode, object keyvalue) @ system.data.entity.core.entitykey.gethashcode() @ system.collections.generic.genericequalitycomparer`1.gethashcode(t obj) @ system.collections.generic.dictionary`2.findentry(tkey key) @ system.collections.generic.dictionary`2.trygetvalue(tkey key, tvalue& value) @ system.data.entity.core.objects.objectstatemanager.trygetentityentry(entitykey key, entityentry& entry) @ system.data.entity.core.objects.objectstatemanager.findentityentry(entitykey key) @ system.data.entity.core.common.internal.materialization.shaper.handleentityappendonly[tentity](func`2 constructentitydelegate, entitykey entitykey, entityset entityset) @ lambda_method(closure , shaper ) @ system.data.entity.core.common.internal.materialization.coordinator`1.readnextelement(shaper shaper) @ system.data.entity.core.common.internal.materialization.shaper`1.simpleenumerator.movenext() @ system.data.entity.internal.lazyenumerator`1.movenext()

the problem model (tree in example above) has 1 ore more properties not nullable (and possibly marked not nullable in mapping) but corresponding column in data store nullable. exception manifest there record being retrieved had null value 1 of column(s).

  • model fix - when updating model sure use nullable<t> or ? nullable value types , if have mappings defined (either via attributes or in types inherit entitytypeconfiguration) specify property optional there.
  • data store fix - alternatively change data store schema , data align expected in model.

-

Comments

Post a Comment

Popular posts from this blog

unity3d - Rotate an object to face an opposite direction -

i have object , b. when click on object b, rotates object b (a faces b). b doesn't face a. need following : when faces b, need face opposite direction. have code rotating @ b. how rotate face opposite direction after that? vector3 targetdirection = target - transform.position; float step = speed * time.deltatime; vector3 newdirection = vector3.rotatetowards (turretdome.transform.forward, targetdirection, step, 0.0f); turretdome.transform.rotation = quaternion.lookrotation (newdirection); you object facing object b, want inverse direction of object after that? objecta.transform.rotation = quaternion.inverse(objecta.transform.rotation) but lets assume example turretdome object a, (negate direction): turretdome.transform.rotation = quaternion.lookrotation (-newdirection); naturally, both of these snippets not show how smoothen rotation, seem know how use time.deltatime. just incase unsure, quaternion.lerp this
Read more

angular - Is it possible to get native element for formControl? -

i've got angular2 reactive form . created formcontrol s , assigned input fields by [formcontrol]=... . understand creates nativeelement <-> formcontrol link. my question: possible nativeelement formcontrol ? wanna myformcontrol.nativeelement.focus() i can share 1 terrible solution works me. in reactive forms can use either 1) formcontroldirective ts mycontrol = new formcontrol('') template <input type="text" [formcontrol]="mycontrol"> or 2) formcontrolname ts myform: formgroup; constructor(private fb: formbuilder) {} ngoninit() { this.myform = this.fb.group({ foo: '' }); } template <form [formgroup]="myform"> <input type="text" formcontrolname="foo"> </form> so these directives write patch like 1) formcontroldirective const originformcontrolngonchanges = formcontroldirective.prototype.ngonchanges; formcontroldirective.proto
Read more

javascript - Why jQuery Select box change event is now working? -

i working on product filters user select select box according his/her preference not getting selected value user in jquery. html code:- <select name="product_filter" id="product_filter"> <option value="price_low_first">price : low high</option> <option value="price_high_first">price : high low</option> <option value="latest">latest</option> <option value="popular">most popular</option> </select> jquery code: $(function () { $("#product_filter").change(function () { alert("hi") var selectedtext = $(this).find("option:selected").text(); var selectedvalue = $(this).val(); alert("selected text: " + selectedtext + " value: " + selectedvalue); }); }); hi believe code perfect. once please check jquery.min.js
Read more