我正在使用 EF6，由于 AddRange() 方法的速度较慢，我需要使用 BulkInsert。所以我通过 here 为 EF6 添加了 BulkInsert 的 NuGet 包.

添加 dll 后我收到的第一件事是这个警告:

Found conflicts between different versions of the same dependent assembly. Please set the "AutoGenerateBindingRedirects" property to true in the project file.

我制作了一个 List 包含我所有的 Contact 实体，即需要添加的 contactsToInsert(我的联系人在另一个表中有一个外键， 也)。当我尝试运行以下代码时，我收到一个 KeyNotFoundException，它声称“字典中不存在给定的键”。

using (var db = new Entities(myConnectionString))
{
    db.BulkInsert(contactsToInsert);
    db.SaveChanges();
}

NB. 我在 BackgroundWorker 中运行 BulkInsert。根据 this fix 判断，这可能是问题的原因吗？ ？

堆栈跟踪:

   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at EntityFramework.MappingAPI.Mappers.MapperBase.BindForeignKeys() in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Mappers\MapperBase.cs:line 603
   at EntityFramework.MappingAPI.Mappings.DbMapping..ctor(DbContext context) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Mappings\DbMapping.cs:line 101
   at EntityFramework.MappingAPI.EfMap.Get(DbContext context) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\EfMap.cs:line 60
   at EntityFramework.MappingAPI.Extensions.MappingApiExtensions.Db(DbContext ctx, Type type) in c:\dev\EntityFramework.MappingAPI\trunk\src\EntityFramework.MappingAPI\Extensions\MappingApiExtensions.cs:line 51
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
   at EntityFramework.BulkInsert.Helpers.MappedDataReader`1..ctor(IEnumerable`1 enumerable, IEfBulkInsertProvider provider) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Helpers\MappedDataReader.cs:line 58
   at EntityFramework.BulkInsert.Providers.EfSqlBulkInsertProviderWithMappedDataReader.Run[T](IEnumerable`1 entities, SqlTransaction transaction, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\EfSqlBulkInsertProviderWithMappedDataReader.cs:line 22
   at EntityFramework.BulkInsert.Providers.ProviderBase`2.Run[T](IEnumerable`1 entities, IDbTransaction transaction, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\ProviderBase.cs:line 77
   at EntityFramework.BulkInsert.Providers.ProviderBase`2.Run[T](IEnumerable`1 entities, BulkInsertOptions options) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Providers\ProviderBase.cs:line 109
   at EntityFramework.BulkInsert.Extensions.BulkInsertExtension.BulkInsert[T](DbContext context, IEnumerable`1 entities, SqlBulkCopyOptions sqlBulkCopyOptions, Nullable`1 batchSize) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Extensions\BulkInsertExtension.cs:line 95
   at EntityFramework.BulkInsert.Extensions.BulkInsertExtension.BulkInsert[T](DbContext context, IEnumerable`1 entities, Nullable`1 batchSize) in c:\dev\EntityFramework.BulkInsert\dev\Src\EntityFramework.BulkInsert\Extensions\BulkInsertExtension.cs:line 75
   at Prospect.Update.bw_DoWork(Object sender, DoWorkEventArgs e) in c:\Users\pedram.mobedi\Documents\Visual Studio 2013\Projects\Prospect\Update.cs:line 546
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)

最佳答案

修改了 this blog post 中的代码，这是在 BulkInsert() 上遇到相同的 “The given key was not present in the dictionary” 错误后对我的 Code First Fluent API 设置起作用的方法。这里唯一的依赖项是上述帖子的 DataExtensions 片段中的 ToDataTable() 扩展方法。

相关部分是 GetColumnMappings() 方法，它获取 POCO 类属性的首选名称(您在代码中指定的名称)作为源列名称(在enumerable-turned-datatable) 并将其与元数据成员的名称(数据库列名称)配对作为目标列名称。

GetColumnMappings():

private IEnumerable<SqlBulkCopyColumnMapping> GetColumnMappings<T>()
{
    var storageMetadata = ((EntityConnection)objectContext.Connection).GetMetadataWorkspace().GetItems(DataSpace.SSpace);
    var entityPropMembers = storageMetadata
        .Where(s => (s.BuiltInTypeKind == BuiltInTypeKind.EntityType))
        .Select(s => (EntityType)s)
        .Where(p => p.Name == typeof(T).Name)
        .Select(p => (IEnumerable<EdmMember>)(p.MetadataProperties["Members"].Value))
        .First();

    var sourceColumns = entityPropMembers.Select(m => (string)m.MetadataProperties["PreferredName"].Value);
    var destinationColumns = entityPropMembers.Select(m => m.Name);

    return Enumerable.Zip(sourceColumns, destinationColumns, (s, d) => new SqlBulkCopyColumnMapping(s, d));
}

完整代码:

// Modified from: https://ruijarimba.wordpress.com/2012/03/25/bulk-insert-dot-net-applications-part1 and
// https://ruijarimba.wordpress.com/2012/03/18/entity-framework-get-mapped-table-name-from-an-entity/

internal class BulkInserter
{
    private readonly ObjectContext objectContext;

    private readonly IDbConnection connection;

    internal BulkInserter(DbContext contextAdapter)
    {
        objectContext = ((IObjectContextAdapter)contextAdapter).ObjectContext;
        connection = contextAdapter.Database.Connection;
    }

    public void Insert<T>(IEnumerable<T> items) where T : class
    {
        EnsureOpenConnection();
        using (var bulkCopy = new SqlBulkCopy((SqlConnection)connection)
        {
            DestinationTableName = GetTableName<T>(),
        })
        {
            foreach (var mapping in GetColumnMappings<T>())
            {
                bulkCopy.ColumnMappings.Add(mapping);
            }

            bulkCopy.WriteToServer(items.ToDataTable());
        }
    }
    private void EnsureOpenConnection()
    {
        if (connection.State == ConnectionState.Closed)
        {
            connection.Open();
        }
    }

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
    private string GetTableName<T>() where T : class
    {
        string sql = objectContext.CreateObjectSet<T>().ToTraceString();
        Regex regex = new Regex("FROM (?<table>.*) AS");
        Match match = regex.Match(sql);

        string table = match.Groups["table"].Value;
        return table;
    }

    private IEnumerable<SqlBulkCopyColumnMapping> GetColumnMappings<T>()
    {
        var storageMetadata = ((EntityConnection)objectContext.Connection).GetMetadataWorkspace().GetItems(DataSpace.SSpace);
        var entityPropMembers = storageMetadata
            .Where(s => (s.BuiltInTypeKind == BuiltInTypeKind.EntityType))
            .Select(s => (EntityType)s)
            .Where(p => p.Name == typeof(T).Name)
            .Select(p => (IEnumerable<EdmMember>)(p.MetadataProperties["Members"].Value))
            .First();

        var sourceColumns = entityPropMembers.Select(m => (string)m.MetadataProperties["PreferredName"].Value);
        var destinationColumns = entityPropMembers.Select(m => m.Name);

        return Enumerable.Zip(sourceColumns, destinationColumns, (s, d) => new SqlBulkCopyColumnMapping(s, d));
    }
}

关于c# - Entity Framework 批量插入抛出 KeyNotFoundException 错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32225183/