Entity Framework selection query
Solution 1
Using Linq To Entities with lambda expression:
var result = dBContext.Account.Where(a=> a.email == "" && a.password =="").ToList();
Using Linq To Entities the less fancy way:
var result = (from a in dBContext.Account
where a.email == "" && a.password ==""
select a).ToList();
Lambda expressions are used most of the time. Some people find lambda's less readable. I think it's more a personal taste that depends from your background.
EDIT:
dbContext should be replaced by the name you gave your dbContext/Entities when setting up your Entitiy framework EDMX or Code First Classes.
Account should be replaced by the name of your table/Entity
To loop and edit the results you can do:
foreach(var account in results)
{
//do something with the properties
account.email = "[email protected]"
}
//store the changes again in the db
dbContext.SaveChanges();
Solution 2
Use linq ex:
List<User> result = dbContext.Users.Where(o=> o.email == "" && o.password=="").ToList();
foreach(User u in result)
{
// do stuff
}
User u = new User();
u.Email = "[email protected]";
dbContext.Users.Add(u);
dbContext.Save(); //I think its Save()..
Solution 3
Have to use Linq query like
var data= dBContext.Account.Where(a=> a.email == "" && a.password =="").ToList();
.ToList()
will give your entire data that comes under your where condition or filter.
Now for that you return DataTable
and easily apply a for
condtion based on your DataTable
values.
Solution 4
DataTable tempData = (DataTable)grdRecords.DataSource;
var query = from r in tempData.AsEnumerable()
where r.Field<string>("UserName") != "TestUsername" &&
r.Field<string>("Password") != "TestPassword"
select r;
DataTable newDT = query.CopyToDataTable();
Solution 5
use linq query as follows
IList<Users> Users = dbContext.Users.Where(x=> x.email == "" && x.password=="").ToList();
then if you want to convert into DataTable just call following generic method do convert it
public DataTable ToDataTable<T>(IList<T> data)// T is any generic type
{
PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
for (int i = 0; i < props.Count; i++)
{
PropertyDescriptor prop = props[i];
table.Columns.Add(prop.Name, prop.PropertyType);
}
object[] values = new object[props.Count];
foreach (T item in data)
{
for (int i = 0; i < values.Length; i++)
{
values[i] = props[i].GetValue(item);
}
table.Rows.Add(values);
}
return table;
}
Mer Hardik
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Updated on August 16, 2020Comments
-
Mer Hardik over 3 years
I am making a simple application for insert, update, delete, select data with
Entity Framework
I already made insertion, deletion and select all data.Now I want to select with where condition with filter of two fields
For ex : I have table withuserid username password email
Now need selection like
where email = "" and password = ""
I know how to write query in SQL but having not clues with
entity framework
.
Also need to store this result in datatable and looping solution both for learning purpose.
This can help many beginners