一个棘手的(和令人沮丧的问题) - 也许你们这些人可能是足够聪明来解决它:实体框架6 - Npgsql的 - 连接字符串错误
问题
我希望能够读/使用Entity Frameworks写入我的数据库。我在Heroku上运行了一个简单的应用程序rails(简单的脚手架)。我想连接到这个数据库并操作记录。好消息是,我可以使用npgsql成功连接到该数据库。坏消息是我不能用Entity Frameworks来做。这是我收到的错误:
System.Data.Entity.Core.ProviderIncompatibleException:错误 同时获得由数据库提供信息时发生。此 可能由实体框架使用不正确的连接 字符串引起。检查内部例外以获取详细信息,并确保 连接字符串正确。 ---> System.Data.Entity.Core.ProviderIncompatibleException:提供程序 未返回ProviderManifestToken字符串。 ---> System.IO.FileLoadException:无法加载文件或程序集'Npgsql, 版本= 3.1.2.0,Culture = neutral,PublicKeyToken = 5d8b90d52f46fda7'或 其依赖项之一。找到的程序集清单定义 与程序集引用不匹配。 (异常来自HRESULT: 0x80131040)
这里是堆栈跟踪:
at Npgsql.NpgsqlServices.GetDbProviderManifestToken(DbConnection connection)
at System.Data.Entity.Core.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection)
--- End of inner exception stack trace ---
at System.Data.Entity.Core.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection)
at System.Data.Entity.Utilities.DbProviderServicesExtensions.GetProviderManifestTokenChecked(DbProviderServices providerServices, DbConnection connection)
--- End of inner exception stack trace ---
at System.Data.Entity.Utilities.DbProviderServicesExtensions.GetProviderManifestTokenChecked(DbProviderServices providerServices, DbConnection connection)
at System.Data.Entity.Infrastructure.DefaultManifestTokenResolver.<>c__DisplayClass1.<ResolveManifestToken>b__0(Tuple`3 k)
at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
at System.Data.Entity.Infrastructure.DefaultManifestTokenResolver.ResolveManifestToken(DbConnection connection)
at System.Data.Entity.Utilities.DbConnectionExtensions.GetProviderInfo(DbConnection connection, DbProviderManifest& providerManifest)
at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.InternalContext.Initialize()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.Select[TSource,TResult](IQueryable`1 source, Expression`1 selector)
at ge_EntityFrameworkTest.Program.<Test>d__4.MoveNext() in c:\Users\Koshy\Documents\Visual Studio 2013\Projects\Practice\ge-EntityFrameworkTest\ge-EntityFrameworkTest\Program.cs:line 118
这里是我的连接字符串:
NpgsqlConnectionStringBuilder sqlBuilder = new NpgsqlConnectionStringBuilder();
sqlBuilder.Username = user;
sqlBuilder.Password = password;
sqlBuilder.Host = host;
sqlBuilder.Port = Int32.Parse(port);
sqlBuilder.Database = database;
sqlBuilder.Pooling = true;
sqlBuilder.UseSslStream = true;
sqlBuilder.SslMode = Npgsql.SslMode.Require;
sqlBuilder.TrustServerCertificate = true;
这是我的“Hello world”,我用于连接并从我的数据库读取(从玩家表)。它成功地将“Lionel Messi”打印到控制台上。大!
#region connectingAndReadingDatabase
using (var conn = new NpgsqlConnection(sqlBuilder.ToString()))
{
conn.Open();
using (var cmd = new NpgsqlCommand())
{
cmd.Connection = conn;
// Retrieve all rows
cmd.CommandText = "SELECT * FROM players";
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
Console.WriteLine(reader.GetString(1));
}
}
}
}
#endregion
问题是当我尝试使用实体框架。它带着痛苦的错误大规模地失败。我使用完全相同的连接字符串,并且不能为我的生活找出我要出错的地方。也许你可能很容易发现问题?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Net.Http;
using Newtonsoft.Json;
using Npgsql;
using System.Data.Entity;
using System.Data.Common;
using System.ComponentModel.DataAnnotations.Schema;
using System.ComponentModel.DataAnnotations;
using System.Configuration;
using System.Data.Entity.ModelConfiguration.Conventions;
// Here is the code pertaining to my hello world entity framework example:
[Table("players", Schema = "public")]
public class Player
{
[Key]
[Column("id")]
public int id { get; set; }
[Column("name")]
public string Name { get; set; }
[Column("team")]
public string Team { get; set; }
public Player() { }
}
class NpgsqlConfiguration : System.Data.Entity.DbConfiguration
{
public NpgsqlConfiguration()
{
SetProviderServices ("Npgsql", Npgsql.NpgsqlServices.Instance);
SetProviderFactory ("Npgsql", Npgsql.NpgsqlFactory.Instance);
SetDefaultConnectionFactory (new Npgsql.NpgsqlConnectionFactory());
}
}
[DbConfigurationType(typeof(NpgsqlConfiguration))]
public class PlayerContext : DbContext
{
public PlayerContext(DbConnection connection): base(connection, true)
{
}
public DbSet<Player> Players { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
//modelBuilder.Conventions.Add<CascadeDeleteAttributeConvention>();
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.HasDefaultSchema("public");
base.OnModelCreating(modelBuilder);
}
}
这里是我的app.config文件
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="v12.0" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
<provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
</providers>
</entityFramework>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Npgsql" publicKeyToken="5d8b90d52f46fda7" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-3.1.0.0" newVersion="3.1.0.0" />
</dependentAssembly>
</assemblyBinding>
</runtime>
<system.data>
<DbProviderFactories>
<add name="Npgsql Data Provider"
invariant="Npgsql"
description="Data Provider for PostgreSQL"
type="Npgsql.NpgsqlFactory, Npgsql" />
</DbProviderFactories>
</system.data>
<connectionStrings>
<add name="PlayerContext" connectionString="Username=hjanadgkizjmgf;Password=password;Host=ec2-54-235-250-156.compute-1.amazonaws.com;Port=5432;Database=deek4ap6cf2a1;Pooling=true;Use SSL Stream=True;SSL Mode=Require;TrustServerCertificate=True;" providerName="Npgsql" />
</connectionStrings>
</configuration>
当我通过直接在连接字符串中 - 这工作这么好提前检索记录的同一个,我得到这个奇怪的例外:
“关键字不被支持'用户名'” - 显然是指连接字符串传入的 。
using (var db = new PlayerContext(sqlBuilder.ToString()))
{ // etc }
而且奇怪的是,我在编译之前发出警告:
“警告不同版本的同一 依赖程序集的,可能无法得到解决之间1个发现冲突。当日志详细程度设置为 详细信息时,会在构建日志中列出这些参考 冲突。 pg-EF-test2“或许与Npgsql有关?
任何援助将不胜感激。
谢谢,终于找到了这1天试图解决我的多供应商多上下文建立搜索〜之后,实际上这是我唯一的问题。 (从3.1.0升级到3.2.6的Npgsql) –