AutoMapper with Entity Framework - entity-framework

I am using AutoMapper v6.1.1 with EntityFramework v6.1.3 when I try to map my EF Entities and try to convert it to the DTO's I am getting following error:
AutoMapperMappingException: Missing type map configuration or unsupported mapping.
Similar issue here but didn't helped me. This is something to do with EF dynamic proxy have different type. Something like this:
System.Data.Entity.DynamicProxies.Gender_3419AAE86B58120AA2983DA212CFFEC4E42296DA14DE0836B3E25D7C6252EF18
CODE:
Mapper.Initialize(c => c.CreateMap<MyEntity, MyDTO>());
using (var context = new DbContext())
{
var entities= context.MyTable.GetAll().ToList();
var myDTOs = Mapper.Map<List<MyEntity>, List<MyDTO>>(entities); // <---error here
}
Can someone help me how to handle Entity Framework dynamic proxy with AutoMapper.
Thank you.

Usually you do this sort of mapping on individual objects rather than lists. Try something like:
var myDTOs = entities.Select(e => Mapper.Map<MyEntity, MyDTO>(e)).ToList();

Related

Creating new entity framework record from related object

Is there a way to use SetValues() when creating an entity framework object.
I have a class with same field definitions as my entity framework class and found this explanation of an easier way to update ef records using the SetValues function.
https://researchaholic.com/2013/02/06/entity-framework-5-easier-way-to-update-record/
The question I have is this: Is there a similar way to create new ef records without specifying every field like this:
var newItm = new Import.EntityClasses.ImportSiteList {
SiteId = ssItm.SiteId,
OrganizationId = ssItm.OrganizationId,
TimeZoneId = ssItm.TimeZoneId
};
tbl.Add(newItm);
This is how you can do
var newItm = new Import.EntityClasses.ImportSiteList();
context.Entry(newItm).State = EntityState.Added;
context.Entry(newItm).CurrentValues.SetValues(ssItm);
context.SaveChanges();
Hope it helps.

How to Determine a property is ComplexType?

I want to implement an IsComplexType() method, which check if the given property from an entity is a ComplexType.
After reading Entity Framework's source code, i find it has implemented one in the "Helper" class, but the class is "internal", so i can't use it outside Entity Framework project.
I wonder if there's a public API in Entity Framework which enable me to do this. If not, how can i implement it?
Try this :
var dbContext = new DbContext("ConnectionString");
var complexType = dbContext.Entry(TEntity).ComplexProperty("ProperyName");
if (complexType != null)
{
// This is a Complex Type
}
Hope this help.

EF 4.0 Dynamic Proxies POCO Object Does not match target type

I am using EF 4.0 and POCO's. I stumbled across this error while inserting to records into the data base.
Property accessor 'QualityReasonID' on object 'BI.Entities.QualityReason' threw the following exception:'Object does not match target type.'
There errors occur on the Databind to a GridView after saving a new record to the database. I identified what is happening but I am not sure WHY it is occurring or If I am using EF/POCO's incorrectly. Any insight would be appreciated.
The exception is occuring because the object types in the IEnumerable are not the same.
The orginal entrys in the table are of type System.Data.Entity.DynamicProxies.QualityReason_E483AD567288B459706092F1825F53B1F93C65C5329F8095DD1D848B5D039F04}
While the new one is BI.Entities.QuailtyReason.
Here is how I insert the new object.
public void createQualityReason(QualityReason qReasons)
{
dbcontext.QualityReasons.AddObject(qReasons);
dbcontext.SaveChanges();
}
I resolved the error by changing the fetch code from:
public IEnumerable<QualityReason> fetchQualityReasons()
{
IEnumerable<QualityReason> queryReasons = dbcontext.QualityReasons.AsEnumerable();
return queryReasons;
}
to
public IEnumerable<QualityReason> fetchQualityReasons()
{
IEnumerable<QualityReason> queryReasons = from data in dbcontext.QualityReasons.AsEnumerable()
select new QualityReason
{
QualityReasonID = data.QualityReasonID,
QualityReasonName = data.QualityReasonName
};
return queryReasons;
}
So to get around the error I have to select into the POCO class explicitly each time. This feels like I am going something wrong. Any thoughts?
The error is caused because GridView does not handle polymorphic datasources when using boundfields. So you have two options
Use TemplateFields instead which can handle polymorphic datasources, this may changing some of your front end code and GridView events.
Use Linq to create a non-polymorphic databsource that the boundfields can handle
So instead of using something like ti
gvGroups.DataSource = ProductHelper.Get()
gvGroups.DataBind();
var query = from p in ProductHelper.Get()
select new {p.ProductId, p.ProductName, p.ProductDesc, p.ProductLink};
gvGroups.DataSource = query;
gvGroups.DataBind();
I don't know if the problem has been solved yet, but I've had the same problem with my (POCO) "Scenario" class.
The problem disappeared when using a context.CreateObject<Scenario> to create the (POCO) object i.s.o. a .... = new Scenario().
Faced the same issue today and used Value Injecter to solve it. It's as simple as:
var dynamicProxyMember = _repository.FindOne<Member>(m=>m.Id = 1);
var member = new Member().InjectFrom(dynamicProxyMember) as Member;
That's it :)

How to save child relationship entities in the Entity Framework

I have an Entity Framework v1 project. I have two entities (Roles and Permissions), which have a many-to-many relationship with each other. I pass in a object to be saved (through a WCF call, I do not create it from a context myself), which has new entries in the many-to-many relationship.
I use "context.ApplyPropertyChanges" to update the record with the new properties. I know that this does not update relationships though. I attempt to either do a ChildCollection.Add(relatedObject); or ChildCollection.Attach(relatedObject).
When I use the "Add" method, I get the error that: The object cannot be added to the ObjectStateManager because it already has an EntityKey. Use ObjectContext.Attach to attach an object that has an existing key.
When I use the "Attach" method, I get the error that: The object cannot be added to the ObjectStateManager because it already has an EntityKey. Use ObjectContext.Attach to attach an object that has an existing key.
I am getting quite frustrated, and I think I can hear the Entity Framework laughing at me.
Does anyone know how I can resolve this?
MyRole x = context.Roles.FirstOrDefault(a => a.RoleId == this.RoleId);
context.ApplyPropertyChanges("Roles", this);
foreach (MyPermission p in this.Permissions)
{
x.Permissions.Add(p);
// ^ or v
x.Permissions.Attach(p);
}
context.SaveChanges();
Thanks.
Wow. After 20 or so straight hours on this problem, I'm starting to hate the Entity Framework. Here is the code that appears to be working currently. I would appreciate any advice on how to make this more streamlined.
I did rework the WCF service so that there is only the one data context. Thanks Craig.
Then I had to change the code to the following:
MyRole x = context.Roles.FirstOrDefault(a => a.RoleId == this.RoleId);
if (x == null) // inserting
{
MyApplication t = this.Application;
this.Application = null;
context.Attach(t);
this.Application = t;
}
else // updating
{
context.ApplyPropertyChanges("Roles", this);
x.Permissions.Load();
IEnumerable<Guid> oldPerms = x.Permissions.Select(y => y.PermissionId);
List<MyPermission> newPerms = this.Permissions.Where(y => !oldPerms.Contains(y.PermissionId)).ToList();
IEnumerable<Guid> curPerms = this.Permissions.Select(y => y.PermissionId);
List<MyPermission> deletedPerms = x.Permissions.Where(y => !curPerms.Contains(y.PermissionId)).ToList();
// new
foreach (MyPermission p in newPerms)
{
x.Permissions.Add(context.Permissions.First(z => z.PermissionId == p.PermissionId));
}
// deleted
foreach (MyPermission p in deletedPerms)
{
x.Permissions.Remove(context.Permissions.First(z => z.PermissionId == p.PermissionId));
}
}
You are using multiple ObjectContexts concurrently (the variable context and whereever this came from). Don't do that. It will only make things very difficult for you. Use one ObjectContext at a time.
I can give more specific advice if you show more code.
I suspect you are getting the errors because the ObjectContext thinks you are trying to add a new entity but finds it already has a EntityKey. I use the AttachTo method of the ObjectContext to attach my already existing entities to their EntitySet. I have had results generating my entities from stubs or hitting the database. This way when you add the entity to the navigation property on your entity, the ObjectContext finds the entity in it's EntitySet and knows it is an existing entity and not a new one. I don't know if this is clear. I could post some code if it would help. As Mr Stuntz said in his answer, posting more of your code would help.

How to do server side pre filtering with Entity Framework and Dynamic Data?

I use Entity Framework 4.0 and need to prefilter all queries using TennantId. I modified T4 template to add pre-filter to all ObjectSets like so and it works for "regular" part of the application.
public ObjectSet<Category> Categories
{
get
{
if ((_Categories == null))
{
_Categories = base.CreateObjectSet<Category>("Categories");
_Categories = _Categories.Where("it.TenantId = 10");
}
return _Categories;
}
}
The problem I have is that ASP.NET Dynamic Data doesn't invoke these methods and goes directly to CreateQuery which I cannot override.
Is there any way to prefilter data in this scenario?
You can set a condition for each entity in your Edm and EF will automatically append that condition in the "Where" clause of all the queries it generates.
See my answer to here that might help you.