expressappframework-403168-business-model-design-orm-non-persistent-objects-how-to-display-a-detail-view-with-data-from-a-stored-procedure-from-the-navigation.md
This example demonstrates how to show a Detail View for data fetched from a stored procedure from the Navigation.
This example uses the Northwind database and Non-Persistent Objects to store data from the stored procedure. The stored procedure is defined as follows:
CREATE PROCEDURE GetEmployee
@ID INT
AS
BEGIN
SET NOCOUNT ON;
SELECT * FROM Employees
WHERE EmployeeID = @ID
END
GO
In the platform-agnostic MySolution.Module project, create the following non-persistent class:
Handle the OnObjectSpaceCreated event in the Application Builder code to subscribe to the NonPersistentObjectSpace events as described in the following topic: How to: Display a Non-Persistent Object’s Detail View.
ORM-dependent code executes a stored procedure (the code uses Session in XPO and DbContext in EF Core). You can access the Session or DbContext through the corresponding persistent ObjectSpace. To allow the NonPersistentObjectSpace to access persistent ObjectSpaces, populate the CompositeObjectSpace.AdditionalObjectSpaces collection in the ObjectSpaceCreated event handler.
To separate the Module code from business logic to fetch data, create an adapter class to handle the NonPersistentObjectSpace events. Handle the NonPersistentObjectSpace.ObjectByKeyGetting event to return a displayed object.
Add a navigation item for the MyNonPersistentObject Detail View with the object key as described in the following topic: How to: Display a Non-Persistent Object’s Detail View.
Use the Session.ExecuteQueryWithMetadata method to get data from a stored procedure. This method returns column names along with data. Refer to the following help topic for instructions on how to access data from the ExecuteQueryWithMetadata method: How to: Access Data in SQL Query Results.
Use the XPObjectSpace.Session property to access a Session instance. You can access an XPObjectSpace instance from the CompositeObjectSpace.AdditionalObjectSpaces collection.
using DevExpress.ExpressApp.Xpo;
using DevExpress.Xpo;
using DevExpress.Xpo.DB;
using System.Linq;
class MyNonPersistentObjectAdapter {
// ...
MyNonPersistentObject GetObjectFromSproc(object key) {
XPObjectSpace persistentObjectSpace = objectSpace.AdditionalObjectSpaces.OfType<XPObjectSpace>().First();
Session session = persistentObjectSpace.Session;
SelectedData results = session.ExecuteQueryWithMetadata($"GetEmployee @ID={key}");
Dictionary<string, int> columnNames = new Dictionary<string, int>();
for (int columnIndex = 0; columnIndex < results.ResultSet[0].Rows.Length; columnIndex++) {
string columnName = results.ResultSet[0].Rows[columnIndex].Values[0] as string;
columnNames.Add(columnName, columnIndex);
}
MyNonPersistentObject obj = new MyNonPersistentObject();
if (results.ResultSet[1].Rows.Length > 0) {
SelectStatementResultRow row = results.ResultSet[1].Rows[0];
obj.EmployeeID = (int)row.Values[columnNames["EmployeeID"]];
obj.FirstName = row.Values[columnNames["FirstName"]] as string;
obj.LastName = row.Values[columnNames["LastName"]] as string;
obj.Title = row.Values[columnNames["Title"]] as string;
}
return obj;
}
}
In EF Core, use the DbSet object’s RelationalQueryableExtensions.FromSqlRaw extension method to get data from a stored procedure. Create an entity class that should store data fetched from a stored procedure.
namespace YourSolutionName.Module.BusinessObjects {
public class Employees {
[System.ComponentModel.DataAnnotations.Key]
public virtual int EmployeeID { get; set; }
public virtual string FirstName { get; set; }
public virtual string LastName { get; set; }
public virtual string Title { get; set; }
}
}
// Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.
Add the new entity class to the solution’s DbContext in the YourSolutionName.Module\BusinessObjects\YourSolutionNameDbContext.cs file.
using Microsoft.EntityFrameworkCore;
public class YourSolutionNameEFCoreDbContext : DbContext {
// ...
public DbSet<Employees> Employees { get; set; }
}
Get an EFCoreObjectSpace instance from the CompositeObjectSpace.AdditionalObjectSpaces collection in the GetObjectFromSproc method.
Access the YourSolutionNameEFCoreDbContext instance from the EFCoreObjectSpace.DbContext property.
Call the YourSolutionNameEFCoreDbContext.Employees.FromSqlRaw method to get data from a stored procedure.
using DevExpress.ExpressApp.EFCore;
using Microsoft.EntityFrameworkCore;
class MyNonPersistentObjectAdapter {
// ...
MyNonPersistentObject GetObjectFromSproc(object key) {
EFCoreObjectSpace persistentObjectSpace = objectSpace.AdditionalObjectSpaces.OfType<EFCoreObjectSpace>().First();
YourSolutionNameEFCoreDbContext dbContext = (YourSolutionNameEFCoreDbContext)persistentObjectSpace.DbContext;
IQueryable<Employees> results = dbContext.Employees.FromSqlRaw($"GetEmployee @ID={key}");
MyNonPersistentObject obj = new MyNonPersistentObject();
Employees employees = results.ToList().FirstOrDefault();
if (employees != null) {
obj.EmployeeID = employees.EmployeeID;
obj.FirstName = employees.FirstName;
obj.LastName = employees.LastName;
obj.Title = employees.Title;
}
return obj;
}
}
See Also
How to: Display a List View With Data From a Stored Procedure With a Parameter
How to: Display a List View With Data From a Stored Procedure From the Navigation