Why does this object need a DataContext? - linq-to-sql

This is weird.
regiao C = new regiao();
C.Nome = textBoxNome.Text;
C.Descricao = textBoxDescicao.Text;
C.cidades.AddRange(ListaIN);
mgrRegiao mgr = new mgrRegiao();
mgr.UpdateRegiao(C);
C is a Linq object (code generated by VS2008 in the dbml file) the operation is out of any context. ListaIN in is of type List. That is also the type of C.cidades. The call to mgr.UpdateRegiao creates a context, Copies the contents to objects inside the context and updates the objects. Some of the itens in ListN may have come from a Context (from a query result)
When
C.cidades.AddRange(ListaIN)
Executes I get an exception
Cannot access a disposed object.
Object name: 'DataContext accessed after Dispose.'.
at the line
regiao previousValue = this._regiao.Entity;
in the generated code for the entity regiao set opeation.
[Association(Name="regiao_cidade", Storage="_regiao", ThisKey="IDRegiao", IsForeignKey=true)]
public regiao regiao
{
get
{
return this._regiao.Entity;
}
set
{
regiao previousValue = this._regiao.Entity;
if (((previousValue != value)
|| (this._regiao.HasLoadedOrAssignedValue == false)))
{
this.SendPropertyChanging();
if ((previousValue != null))
{
this._regiao.Entity = null;
previousValue.cidades.Remove(this)
...
Whats wrong ? The object C does not have and never had a context. Why it needs a context and how do I solve this ? Is it because some itens in ListaIN came from the database ? If so, is there a way to detach them ?

OK, so that just the way Linq is, i guess.

Related

how to convert type 'system.linq.iqueryable<byte[]>' to 'byte[]'

In Linq to SQL asp.net, I want to fetch a specific image from database and display on an aspx page. I declared returned type as "var" on the code. So after fetching the image, it assigns image to var type.
Here is the code:
var db = from c in context.Images
where c.imageId == iID
select c.imageData;
return new MemoryStream((byte[])db); ---->> this line of code gives error
It gives this compile error: Cannot convert type 'system.linq.iqueryable' to 'byte[]'.
How can I convert 'system.linq.iqueryable type to byte[] ?
Your problem is that you're selecting a collection of byte[] rather than a single byte[].
Depending on the behavior you want for your application, you can use Single, SingleOrDefault, First, or FirstOrDeault:
var image = context.Images.FirstOrDefault(i => i.imageId == ID);
if(image == null)
{
// Handle the case where no image was found.
//
// First or Single would throw Exceptions in this case
// if that's what you want.
}
else
{
return new MemoryStream(image.imageData);
}
try below line this work for me
var db = (context.Images.FirstOrDefault(i => i.imageId == ID).ImageData

How to avoid "source !=null" when using Code Contracts and Linq To Sql?

I have the following code using a normal data context which works great:
var dc = new myDataContext();
Contract.Assume(dc.Cars!= null);
var cars = (from c in dc.Cars
where c.Owner == 'Jim'
select c).ToList();
However when I convert the filter to an extension method like this:
var dc = new myDataContext();
Contract.Assume(dc.Cars!= null);
var cars = dc.Cars.WithOwner('Jim');
public static IQueryable<Car> WithOwner(this IQueryable<Car> cars, string owner)
{
Contract.Requires(cars != null);
return cars.Where(c => c.Owner == owner);
}
I get the following warning:
warning : CodeContracts: requires unproven: source != null
My guess is that your warning is caused by the owner parameter, rather than the cars. Add a precondition in the WithOwner method to check if owner is not null.
public static IQueryable<Car> WithOwner(IQueryable<Car> cars, string owner)
{
Contract.Requires(cars != null);
Contract.Requires(!string.isNullOrEmpty(owner));
return cars.Where(c => c.Owner = owner);
}
In your first code sample, you have 'Jim' hard-coded, so no problems there because there is not something which can be null.
In your second example you created a method for which the static compiler cannot prove that the source ( being owner ) 'will never be null', as other code might call it with an invalid values.
I wonder how you get the code compiled with the Extension method since you are missing this keyword in your method signature.
public static IQueryable<Car> WithOwner(this IQueryable<Car> cars, string owner)
{
...
}
/KP
Its possible that your code snippet does not completely describe the code you are using.
Consider this snippet instead:
var dc = new myDataContext();
Contract.Assume(dc.Cars!= null);
var models = dc.Cars.WithOwner('Jim').Select(c => c.Model);
public static IQueryable<Car> WithOwner(this IQueryable<Car> cars, string owner)
{
Contract.Requires(cars != null);
return cars.Where(c => c.Owner == owner);
}
In this snipped its likely the runtime will complain with the warning you mentioned, but it is not complaining about Cars possibly being null, it is complaining about the result from WithOwner (passed into Select) possibly being null.
You can satisfy the runtime by ensuring that the result from your extension method will not be null:
Contract.Ensures(Contract.Result<IQueryable<Car>>() != null);
This contract should be ok because Where will not return null, but instead returns an Enumerable.Empty<T>() when there are no matches.
We fixed this a few releases back. The warning was due to some missing contracts around Linq expression construction etc. Linq expression methods have contracts and the C# compiler generates code that calls these methods. If we don't have enough post conditions on the called methods, then you can get these cryptic warnings about code that you don't even know is there (unless you look with ILdasm).

Using Linq to update a List<T> of objects to DB

I have a form that returns me a List of FlatSessie objects
in my edit view I edit a few FlatSessie's and get them returned to my Post method in that List object.
In my DB I have Sessies, which I map using Automapper to FlatSessie's and back
now I can not get linq to make the update to the DB for me.
the code:
[HttpPost]
public ActionResult Sessies(int id, int? modID, int? projID, string schooljaarparam, List<FlatSessie> sl) {
if (ModelState.IsValid) {
foreach (FlatSessie s in sl) { //i run over all FlatSessies which i get
Models.Sessies ses = Mapper.Map<FlatSessie, Sessies>(s); // i map them to the Sessies object
List<Sessies> origReeks = _db.Sessies.Where(p => p.Ses_ID == ses.Ses_ID).ToList(); //i get the original Session by ID. if there is a Session with that ID, if not (the ID will be 0) i do an Insert. if there is i want to do an Update.
if (origReeks.Count > 0) {
//it's an update
UpdateModel(origReeks.First(); //doesnt work
//_db.Sessies.Attach(ses, origReeks.First()); //doesnt work, gives me an error on used ID...
_db.SubmitChanges();
} else {
//no sessies yet, add them, this works.
_db.Sessies.InsertOnSubmit(ses);
_db.SubmitChanges();
}
}
TempData["okmsg"] = "De sessies zijn opgeslagen";
return RedirectToAction("Index");
}
//if not valid, i return the viewdata which i need.
Module m = _db.Modules.First(md => md.Mod_ID == modID.Value);
int antses = m.Mod_AantalSessies.Value;
List<List<SelectListItem>> lpllst = new List<List<SelectListItem>>(antses);
for (int i = 0; i < antses; i++) {
lpllst.Add(MvcApplication.lesplaatsList(schooljaarparam, -1));
}
ViewData["lesplist"] = lpllst;
ViewData["lglist"] = MvcApplication.lesgeverList();
return View(sl);
}
It might work to provide a prefix to UpdateModel (FlatSessie[n], where n is such that it matches the actual input name of the model element in question) so that it knows which properties to map onto the object, but because you are getting a list of these it might not. Have you tried updating the retrieved model using the data from the matching FlatSessie object directly?
Also, once you get this to work, you might want to do a single SubmitChanges for all inserts/updates (outside the loop) so that you get the entire submit wrapped in a single transaction. This will make it easier if there are errors to correct them and resubmit -- since you won't have some changes already committed causing further potential errors.

exception in Linq to sql

my query is :
var ReadAndUnreadMessages =
(from m in MDB.Messages
orderby m.Date descending
where m.ID_Receive == (Guid)USER.ProviderUserKey && m.Delete_Admin == false
select new AllMessages()
{
id = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).ID_Message,
parent = (Guid)(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).ID_Message_Parent,
sender = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).ID_Sender,
receiver = (Guid)USER.ProviderUserKey,
subject = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Subject.Subject1.ToString() == "Other" ?
(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Other_Subject
:
(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Subject.Subject1.ToString(),
body = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Body.Length > 26 ?
(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Body.Substring(0, 25) + "..."
:
(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Body,
date = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).Date.ToShortDateString(),
read =(LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).IsRead,
finished = (LoadMessageChildren(m.ID_Message)[LoadMessageChildren(m.ID_Message).Count - 1] as Message).IsFinished,
count = MessageClass.LoadAll(m.ID_Message).Count
}).ToList();
and exception is :
The argument 'value' was the wrong type. Expected 'Message'. Actual 'System.Object'.
what does meaning it?
LoadMessageChildren :
public static ArrayList LoadMessageChildren(Guid Parent)
{
ArrayList arr = new ArrayList();
Guid id = Parent;
while (id != Guid.Empty)
{
arr.Add(LoadMessage(id));
try
{
id = (Guid)MDB.Messages.Single(a => a.ID_Message_Parent == id).ID_Message;
}
catch
{
id = Guid.Empty;
}
}
return arr;
}
LoadMessage :
public static Message LoadMessage(Guid id)
{
var mess = from m in MDB.Messages
where m.ID_Message == id
select m;
return mess.Single();
}
The code is unreadable, and as a bad case of code repetition (and multiple executions of LoadMessageChildren).
For starters, consider the following:
from m in MDB.Messages
orderby m.Date descending
where m.ID_Receive == (Guid)USER.ProviderUserKey && m.Delete_Admin == false
let children = LoadMessageChildren(m.ID_Message)
let lastChildMessage = children.Last()
select new AllMessages()
{
id = lastChildMessage.ID_Message,
...
}
This may solve your problem, as it is might be caused by using the [] indexer.
Aside from that, it is not clear the posted code is causing the exception.
The only thing I see you using LoadChildMessages() for in the end is to get the child message count... Unless I am wrong I would think you could write it as a join. You doing a lot of queries with in queries that don't seem necessary and are probably causing multiple hits to the database. My question to that would be why isn't there a relationship in your dmbl/sql database so that LinqToSql knows to create a property as a List<Message> ChildMessages
But here is my take:
var query = from message in MDB.Messges
join childmessage in MDB.Messages.Where(child => child.ID_Message_Parent == message.ID_Message) into childMessages
from childMessage in childMessages.DefaultIfEmpty() // This creates a
// left outer join so you get parent messages that don't have any children
where message.ID_Receive == (Guid)USER.ProviderUserKey && message.Delete_Admin == false
select new AllMessages()
{
id = message.ID_Message,
parent = message.ID_Message_Parent,
sender = message.ID_Sender,
receiver = (Guid)USER.ProviderUserKey,
subject = message.Subject.Subject1.ToString() == "Other" ?
message.Other_Subject
:
message.Subject.Subject1.ToString(),
body = message.Body.Length > 26 ?
message.Body.Substring(0, 25) + "..."
:
message.Body,
date = message.Date.ToShortDateString(),
read =message.IsRead,
finished = message.IsFinished,
count = childMessage.Count() // This might have to be this
//count = childMessage == null ? 0 : childMessage.Count()
};
var ReadAndUnreadMessages = query.ToList();
But it's hard to say because I can't run the code... Please respond and let me know if this works.
Note: May I suggest using a class that links to your DataContext.Log property that writes the generated TSQL code to the debugger window. Here is an article on writing your own. It has really help me know when I am making unnecessary calls to the database.
The error is most likely caused by the use of the ArrayList.
The problem is that LINQ was designed to work with generic collections that implement the System.Collections.Generic.IEnumerable<T> interface. The ArrayList is a nongeneric collection that internally stores everything as an Object. So when you retrieve something from the ArrayList you need to cast it to a Message.
Looking at your error message it looks like somewhere a Message object is expected, but the instance in your ArrayList (an Object) is not casted to a Message object when that reference occurs. Also, the ArrayList does not implement the IEnumerable<T> interface which might get you into trouble in certain situations also.
How to fix it?
I suggest changing the implementation of your LoadMessageChildren to use a generic list (List<Message>):
public static List<Message> LoadMessageChildren(Guid Parent)
{
List<Message> arr = new List<Message>();
Guid id = Parent;
while (id != Guid.Empty)
{
arr.Add(LoadMessage(id));
try
{
id = (Guid)MDB.Messages.Single(a => a.ID_Message_Parent == id).ID_Message;
}
catch
{
id = Guid.Empty;
}
}
return arr;
}
You will have to make also change the code that interacts with the generic list in terms of retrieving/referencing items. But that is just syntax. Since equivalent methods for dealist with lists and items exist.
There are also advantages in terms of performance and compile-time validation for switching from ArrayList to List<T>. The ArrayList is basically an inheritance from version 1.0 of the .Net Framework when there was no support for generics and it just get kept in the framework probably for compatibility reasons.
There are greater benefits for using generics.
UPDATED ANSWER:
The "Method 'System.Collections.Generic.List'1[Message] LoadMessageChildren(System.Guid)' has no supported translation to SQL" exception that you are getting is caused by the fact that your LoadMessageChildren method is not mapping to a stored procedure or a user defined function in your database.
You cannot have any regular C# method call inside your LINQ to SQL queries. The LINQ to SQL object model interprets a method found inside your query as either a stored procedure or a user defined function. So the engine is basically looking for a method called LoadMessageChildren that maps to a stored procedure or a user defined function in your database. Because there are no mappings, it tells you that no supported translation to SQL was found. The LINQ to SQL object model link shows you how to use method attributes to map a method that executes a stored procedure.
You have a few choices now:
create stored procedures of your regular C# method calls
rewrite your LINQ query to use joins to select child messages

Explicit construction of entity type '###' in query is not allowed.

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity called "Produccion" from my datacontext in this way:
Demo.View.Data.PRODUCCION pocoProduccion =
(
from m in db.MEDICOXPROMOTORs
join a in db.ATENCIONs on m.cmp equals a.cmp
join e in db.EXAMENXATENCIONs on a.numeroatencion equals e.numeroatencion
join c in db.CITAs on e.numerocita equals c.numerocita
where e.codigo == codigoExamenxAtencion
select new Demo.View.Data.PRODUCCION
{
cmp = a.cmp,
bonificacion = comi,
valorventa = precioEstudio,
codigoestudio = lblCodigoEstudio.Content.ToString(),
codigopaciente = Convert.ToInt32(lblCodigoPaciente.Content.ToString()),
codigoproduccion = Convert.ToInt32(lblNroInforme.Content.ToString()),
codigopromotor = m.codigopromotor,
fecha = Convert.ToDateTime(DateTime.Today.ToShortDateString()),
numeroinforme = Convert.ToInt32(lblNroInforme.Content.ToString()),
revisado = false,
codigozona = (c.codigozona.Value == null ? Convert.ToInt32(c.codigozona) : 0),
codigoclinica = Convert.ToInt32(c.codigoclinica),
codigoclase = e.codigoclase,
}
).FirstOrDefault();
While executing the above code, I'm getting the following error that the stack trace is included:
System.NotSupportedException was caught
Message="The explicit construction of the entity type 'Demo.View.Data.PRODUCCION' in a query is not allowed."
Source="System.Data.Linq"
StackTrace:
en System.Data.Linq.SqlClient.QueryConverter.VisitMemberInit(MemberInitExpression init)
en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
en System.Data.Linq.SqlClient.QueryConverter.Visit(Expression node)
en System.Data.Linq.SqlClient.QueryConverter.VisitSelect(Expression sequence, LambdaExpression selector)
en System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc)
en System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc)
en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
en System.Data.Linq.SqlClient.QueryConverter.Visit(Expression node)
en System.Data.Linq.SqlClient.QueryConverter.VisitFirst(Expression sequence, LambdaExpression lambda, Boolean isFirst)
en System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc)
en System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc)
en System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node)
en System.Data.Linq.SqlClient.QueryConverter.ConvertOuter(Expression node)
en System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations)
en System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)
en System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression)
en System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
en Demo.View.InformeMedico.realizarProduccionInforme(Int32 codigoExamenxAtencion, Double precioEstudio, Int32 comi) en D:\cs_InformeMedico\app\InformeMedico.xaml.cs:línea 602
en Demo.View.InformeMedico.UpdateEstadoEstudio(Int32 codigo, Char state) en D:\cs_InformeMedico\app\InformeMedico.xaml.cs:línea 591
en Demo.View.InformeMedico.btnGuardar_Click(Object sender, RoutedEventArgs e) en D:\cs_InformeMedico\app\InformeMedico.xaml.cs:línea 683
InnerException:
Is that now allowed in LINQ2SQL?
Entities can be created outside of queries and inserted into the data store using a DataContext. You can then retrieve them using queries. However, you can't create entities as part of a query.
I am finding this limitation to be very annoying, and going against the common trend of not using SELECT * in queries.
Still with c# anonymous types there is a workaround, by fetching the objects into an anonymous type, and then copy it over into the correct type.
For example:
var q = from emp in employees where emp.ID !=0
select new {Name = emp.First + " " + emp.Last, EmployeeId = emp.ID }
var r = q.ToList();
List<User> users = new List<User>(r.Select(new User
{
Name = r.Name,
EmployeeId = r.EmployeeId
}));
And in the case when we deal with a single value (as in the situation described in the question) it is even easier, and we just need to copy directly the values:
var q = from emp in employees where emp.ID !=0
select new { Name = emp.First + " " + emp.Last, EmployeeId = emp.ID }
var r = q.FirstOrDefault();
User user = new User { Name = r.Name, EmployeeId = r.ID };
If the name of the properties match the database columns we can do it even simpler in the query, by doing select
var q = from emp in employees where emp.ID !=0
select new { emp.First, emp.Last, emp.ID }
One might go ahead and write a lambda expression that can copy automatically based on the property name, without needing to specify the values explictly.
Here's another workaround:
Make a class that derives from your LINQ to SQL class. I'm assuming that the L2S class that you want to return is Order:
internal class OrderView : Order { }
Now write the query this way:
var query = from o in db.Order
select new OrderView // instead of Order
{
OrderID = o.OrderID,
OrderDate = o.OrderDate,
// etc.
};
Cast the result back into Order, like this:
return query.Cast<Order>().ToList(); // or .FirstOrDefault()
(or use something more sensible, like BLToolkit / LINQ to DB)
Note: I haven't tested to see if tracking works or not; it works to retrieve data, which is what I needed.
I have found that if you do a .ToList() on the query before trying to contruct new objects it works
I just ran into the same issue.
I found a very easy solution.
var a = att as Attachment;
Func<Culture, AttachmentCulture> make =
c => new AttachmentCulture { Culture = c };
var culs = from c in dc.Cultures
let ac = c.AttachmentCultures.SingleOrDefault(
x => x.Attachment == a)
select ac == null ? make(c) : ac;
return culs;
I construct an anonymous type, use IEnumerable (which preserves deferred execution), and then re-consruct the datacontext object. Both Employee and Manager are datacontext objects:
var q = dc.Employees.Where(p => p.IsManager == 1)
.Select(p => new { Id = p.Id, Name = p.Name })
.AsEnumerable()
.Select(item => new Manager() { Id = item.Id, Name = item.Name });
Within the book "70-515 Web Applications Development with Microsoft .NET Framework 4 - Self paced training kit", page 638 has the following example to output results to a strongly typed object:
IEnumerable<User> users = from emp in employees where emp.ID !=0
select new User
{
Name = emp.First + " " + emp.Last,
EmployeeId = emp.ID
}
Mark Pecks advice appears to contradict this book - however, for me this example still displays the above error as well, leaving me somewhat confused. Is this linked to version differences? Any suggestions welcome.
I found another workaround for the problem that even lets you retain your result as IQueryale, so it doesn't actually execute the query until you want it to be executed (like it would with the ToList() method).
So linq doesn't allow you to create an entity as a part of query? You can shift that task to the database itself and create a function that will grab the data you want. After you import the function to your data context, you just need to set the result type to the one you want.
I found out about this when I had to write a piece of code that would produce a IQueryable<T> in which the items don't actually exist in the table containing T.
pbz posted a work around by creating a View class inherited from an entity class that you could be working with. I'm working with a dbml model of a table that has > 200 columns. When I try and return the whole table I get "Root Element missing" errors. I couldn't find anyone who wanted to deal with my particular issue so I was looking at rewriting my entire approach. Just creating a view class for the entitiy class worked in my case.
As pbz suggests : Create a view class that inherits from your entity class. For me this is tbCamp so :
internal class tbCampView : tbCamp
{
}
Then use the view class in your query :
using (var dc = ConnectionClass.Connect(Dev))
{
var camps = dc.tbCamps.Select(s => new tbCampView
{
active = s.active,
idCamp = s.idCamp,
campName = s.campName
});
SmartTableViewer(camps, dg1);
}
private void SmartTableViewer<T>(IEnumerable<T> allRecords)
{
// Build sorted rows back into new table
var table = new DataTable();
// Create columns based on type
if (allRecords is IEnumerable<tbCamp> tbCampRecords)
{
// Get the columns you want
table.Columns.Add("idCamp");
table.Columns.Add("campName");
foreach (var record in tbCampRecords)
{
// Make a new row
var r = table.NewRow();
// Add the contents to each column of the row
r["idCamp"] = record.idCamp;
r["campName"] = record.campName;
// Add the row to the table.
table.Rows.Add(r);
}
}
else
{
MessageBox.Show("Unhandled type. Add support for new data type in SmartTableViewer()");
return;
}
// Update table in grid
dg1.DataSource = table.DefaultView;
}
Here is what happens when you try and create an entity class object in the query.
I didn't want to have to use an anonymous type if I could help it because I wanted the type to be tbCamp. Since tbCampView is of type tbCamp the is operator works well. see Brian Hasden's answer Passing a generic List<> in C#
I'm surprised this is even an issue but with larger tables I run into this error so I thought I would just show it here :
When trying to read this table into memory I get the following error. There are < 2000 rows but the columns are > 200 for each. I don't know if that is an issue or not.
If I just want a few columns I need to create a custom class and handle that which isn't that big of a pain. With the approach pbz provided I don't have to worry about it.
Here is the entire project in case it helps someone.
public partial class Form1 : Form
{
private const bool Dev = true;
public Form1()
{
InitializeComponent();
}
private void btnGetAllCamps_Click(object sender, EventArgs e)
{
using (var dc = ConnectionClass.Connect(Dev))
{
IQueryable<tbCampView> camps = dc.tbCamps.Select(s => new tbCampView
{
// Project columns as needed.
active = s.active,
idCamp = s.idCamp,
campName = s.campName
});
// pass in as a
SmartTableViewer(camps);
}
}
private void SmartTableViewer<T>(IEnumerable<T> allRecords)
{
// Build sorted rows back into new table
var table = new DataTable();
// Create columns based on type
if (allRecords is IEnumerable<tbCamp> tbCampRecords)
{
// Get the columns you want
table.Columns.Add("idCamp");
table.Columns.Add("campName");
foreach (var record in tbCampRecords)
{
//var newRecord = record;
// Make a new row
var r = table.NewRow();
// Add the contents to each column of the row
r["idCamp"] = record.idCamp;
r["campName"] = record.campName;
// Add the row to the table.
table.Rows.Add(r);
}
}
else
{
MessageBox.Show("Unhandled type. Add support for new data type in SmartTableViewer()");
return;
}
// Update table in grid
dg1.DataSource = table.DefaultView;
}
internal class tbCampView : tbCamp
{
}
}