如何使WCF设置与EntityFramework一起使用的连接字符串

本文关键字：连接 字符串 一起 EntityFramework 何使 WCF 设置 | 更新日期: 2023-09-27 18:13:35

使用EntityFramework，我有一个自动生成的文件:

namespace Chaos.Data    
{
public partial class ChaosModel : OpenAccessContext, IChaosModelUnitOfWork
{
    private static string connectionStringName = @"ChaosLibraryConnection";
    private static BackendConfiguration backend = GetBackendConfiguration();
    private static MetadataSource metadataSource = XmlMetadataSource.FromAssemblyResource("EntitiesModel.rlinq");
    public ChaosModel()
        :base(connectionStringName, backend, metadataSource)
    { }
    public ChaosModel(string connection)
        :base(connection, backend, metadataSource)
    { }
     ......................

在WCF服务中，我使用:

namespace Chaos.DataService
{
[ServiceContract]
public class ChaosService 
{
    [OperationContract]
    public IEnumerable<Encountertime> GetEncounterTimes(DateTime? encountertime)
    {
        if (encountertime == null) return null;
        using (var context = new ChaosModel())
        {
            var query = from et in context.Encountertimes
                        where et.Tencounter.Date == ((DateTime)encountertime).Date
                        select et;
           var result = context.CreateDetachedCopy(query.ToList());
            return result;
        }
    }
 .............................

我如何使WCF服务在启动时执行一个方法(一次)，该方法将返回一个新的连接字符串，以便我可以将对ChaosModel()的调用更改为:

using (var context = new ChaosModel(connectionString))

(我正在寻找一种在WCF服务中添加静态构造函数的方法——或者更好的方法?)。

(该方法将确定我所处的网络并构造到网络服务器的适当连接字符串)

注意:我不能修改自动生成的实体文件

如何使WCF设置与EntityFramework一起使用的连接字符串

使用静态构造函数

[ServiceContract]
public class ChaosService 
{
    private static string connectionString;
    static ChaosService(){
        connectionString = your logic...
    }
    [OperationContract]
    public IEnumerable<Encountertime> GetEncounterTimes(DateTime? encountertime)
    {
        using (var context = new ChaosModel(connectionString))
        {
           ...
        }
    }
}

或最终的单例模式:

public class ConnectionInfo
{
    public string ConnectionString { get; private set; }
    private ConnectionInfo()
    {
        var connectionstring = string.Empty;
        //some logic
        this.ConnectionString = connectionstring;
    }
    private static ConnectionInfo current;
    public static ConnectionInfo Current {
        get {
            if (current != null)
                current = new ConnectionInfo();
            return current;
        }
    }
}        
[OperationContract]
public IEnumerable<Encountertime> GetEncounterTimes(DateTime? encountertime)
{
    using (var context = new ChaosModel(ConnectionInfo.Current.ConnectionString))
    {
       ...
    }
}
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