Session.DefaultSession Property
Gets the pre-initialized default session for simple applications.
Namespace: DevExpress.Xpo
Assembly: DevExpress.Xpo.v18.2.dll
Declaration
Property Value
| Type | Description |
|---|---|
| Session | A Session object which is the default session. |
Remarks
This property returns the XpoDefault.Session property value.
Example
The following example demonstrates how to work with transactions.
In this example, the transaction begins when a persistent object is saved. The Session.BeginTransaction method marks the starting point of the transaction. If the value of the persistent object’s Amount property is negative, the Session.RollbackTransaction method is called which completes the transaction discarding all the changes made since the transaction was started.
Otherwise, if the Amount property’s value isn’t negative, the Session.CommitTransaction method is called to complete the transaction and save all the data modifications made.
using System;
using DevExpress.Xpo;
using DevExpress.Xpo.DB;
namespace ConsoleApplication1 {
class Account : XPObject {
public const double DefaultAmount = 100;
private double amount = DefaultAmount;
public Account(Session session) : base(session) { }
public double Amount {
get { return amount; }
set { SetPropertyValue<double>("Amount", ref amount, value); }
}
protected override void OnSaving() {
base.OnSaving();
if (!IsDeleted) {
if (Amount < 0) {
throw new Exception("Negative amount!");
}
}
}
}
class Program {
static void Main(string[] args) {
string connectionString = MSSqlConnectionProvider.GetConnectionString("(local)", "ConsoleApplication1");
XpoDefault.DataLayer = XpoDefault.GetDataLayer(connectionString, AutoCreateOption.DatabaseAndSchema);
TransferAmount(100);
TransferAmount(200);
Console.WriteLine("Press <Enter> to exit");
Console.ReadLine();
}
static void TransferAmount(double amount) {
using (Session session = new Session()) {
Console.WriteLine("Creating Account1 with amount = " + Account.DefaultAmount);
Account account1 = new Account(session);
account1.Save();
Console.WriteLine("Creating Account2 with amount = " + Account.DefaultAmount);
Account account2 = new Account(session);
account2.Save();
Console.WriteLine("");
Console.WriteLine("Beginning the transaction...");
session.BeginTransaction();
try {
Console.WriteLine(String.Format(" Withdrawing {0} from Account1", amount));
account1.Amount -= amount;
account1.Save();
Console.WriteLine(String.Format(" Transferring {0} to Account2", amount));
account2.Amount += amount;
account2.Save();
Console.WriteLine("Committing the transaction...");
session.CommitTransaction();
}
catch (Exception e) {
Console.WriteLine("Exception message: " + e.Message);
Console.WriteLine("Rolling back the transaction");
session.RollbackTransaction();
Console.WriteLine("Reloading the accounts from database...");
account1.Reload();
account2.Reload();
}
Console.WriteLine("Account1 amount: " + account1.Amount);
Console.WriteLine("Account2 amount: " + account2.Amount);
Console.WriteLine();
}
}
}
}
Related GitHub Examples
The following code snippets (auto-collected from DevExpress Examples) contain references to the DefaultSession property.
Note
The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.