ContextManager.cs

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#if !NETSTANDARD2_0 && !NET5_0
//-----------------------------------------------------------------------
// <copyright file="ContextManager.cs" company="Marimer LLC">
//     Copyright (c) Marimer LLC. All rights reserved.
//     Website: https://cslanet.com
// </copyright>
// <summary>Provides an automated way to reuse </summary>
//-----------------------------------------------------------------------
using System;
using Csla.Configuration;
using System.Data.Linq;
 
using Csla.Properties;
 
namespace Csla.Data
{
  public class ContextManager<C> : IDisposable where C : DataContext
  {
    private static object _lock = new object();
    private C _context;
    private string _connectionString;
    private string _label;
 
    public static ContextManager<C> GetManager(string database)
    {
      return GetManager(database, true);
    }
 
    public static ContextManager<C> GetManager(string database, string label)
    {
      return GetManager(database, true, label);
    }
 
    public static ContextManager<C> GetManager(string database, bool isDatabaseName)
    {
      return GetManager(database, isDatabaseName, "default");
    }
 
    public static ContextManager<C> GetManager(string database, bool isDatabaseName, string label)
    {
      if (isDatabaseName)
      {
        var connection = ConfigurationManager.ConnectionStrings[database];
        if (connection == null)
          throw new System.Configuration.ConfigurationErrorsException(String.Format(Resources.DatabaseNameNotFound, database));
        var conn = ConfigurationManager.ConnectionStrings[database].ConnectionString;
        if (string.IsNullOrEmpty(conn))
          throw new System.Configuration.ConfigurationErrorsException(String.Format(Resources.DatabaseNameNotFound, database));
        database = conn;
      }
 
      lock (_lock)
      {
        var contextLabel = GetContextName(database, label);
        ContextManager<C> mgr = null;
        if (ApplicationContext.LocalContext.Contains(contextLabel))
        {
          mgr = (ContextManager<C>)(ApplicationContext.LocalContext[contextLabel]);
 
        }
        else
        {
          mgr = new ContextManager<C>(database, label);
          ApplicationContext.LocalContext[contextLabel] = mgr;
        }
        mgr.AddRef();
        return mgr;
      }
    }
 
    private ContextManager(string connectionString, string label)
    {
      _label = label;
      _connectionString = connectionString;
 
      _context = (C)(Reflection.MethodCaller.CreateInstance(typeof(C), connectionString));
 
    }
 
    private static string GetContextName(string connectionString, string label)
    {
      return "__ctx:" + label + "-" + connectionString;
    }
 
    public C DataContext
    {
      get
      {
        return _context;
      }
    }
 
#region  Reference counting
 
    private int _refCount;
 
    public int RefCount
    {
      get { return _refCount; }
    }
 
    private void AddRef()
    {
      _refCount += 1;
    }
 
    private void DeRef()
    {
 
      lock (_lock)
      {
        _refCount -= 1;
        if (_refCount == 0)
        {
          _context.Dispose();
          ApplicationContext.LocalContext.Remove(GetContextName(_connectionString, _label));
        }
      }
 
    }
 
#endregion
 
#region  IDisposable
 
    public void Dispose()
    {
      DeRef();
    }
 
#endregion
 
  }
}
#endif