如何配置EF代码首先不映射特定类型? [英] How to configure EF Code First to not map a specific type?
问题描述
var dbContext = new MyDbContext();
var list = dbContext.Set< TEntity>()。ToList();
从我最近修改的代码中我明白,因为我向基类添加了一个事件导致所有问题:
public PropertyChangedEventHandler PropertyChangedEvent {get;组;
将NotMapped属性应用到上述属性,我的代码现在正在重新工作。
现在我想知道是否有自动地告诉EntityFramework不映射特定类型的属性(这不是我自己的类型,我不能应用任何属性到.Net的类型)
异常:
序列不包含任何元素。
在System.Linq.Enumerable.First [TSource](IEnumerable`1源,Func`2谓词)
在System.Data.Entity.ModelConfiguration.Edm.Services.StructuralTypeMappingGenerator.GetEntityTypeMappingInHierarchy (DbDatabaseMapping databaseMapping,EdmEntityType entityType)
在System.Data.Entity.ModelConfiguration.Edm.Services.AssociationTypeMappingGenerator.GenerateIndependentAssociationType(EdmAssociationType关联类型,DbDatabaseMapping数据库映射)
在System.Data.Entity.ModelConfiguration.Edm.Services .AssociationTypeMappingGenerator.Generate(EdmAssociationType associationType,DbDatabaseMapping databaseMapping)
在System.Data.Entity.ModelConfiguration.Edm.Services.DatabaseMappingGenerator.GenerateAssociationTypes(EdmModel模型,DbDatabaseMapping数据库映射)
在System.Data.Entity.ModelConfiguration .Edm.Services.DatabaseMappingGenerator.Generate(EdmModel模型)
在System.Data.Entity.ModelConfiguration.Edm.EdmModelExtensions.G enerateDatabaseMapping(EdmModel模型,DbProviderManifest providerManifest)
在System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest,DbProviderInfo providerInfo)
在System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
在System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
在System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput输入)
在System.Data.Entity。 Internal.LazyInternalContext.InitializeContext()
在System.Data.Entity.Internal.InternalContext.Initialize()
在System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
在System.Data.Entity.Internal.Linq.InternalSet`1.GetEnumerator()
在System.Data.Entity。 Infrastructure.DbQuery`1.System.Collections.Generic.IEnumerable< TResult> .GetEnumerator()
您可以使用 Ignore
方法 DbModelBuilder
以排除类型被映射。
public class MyContext:DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Ignore< PropertyChangedEventHandler>();
}
}
I was getting the following error when runing such this code:
var dbContext = new MyDbContext();
var list = dbContext.Set<TEntity>().ToList();
From the changes I made recently to codes I understood that because I added an event to the base class it causes all the problems:
public PropertyChangedEventHandler PropertyChangedEvent { get; set; }
Applying the NotMapped attribute to the above property my codes now are working again.
Now I want to know if there is anyway to autmatically tell EntityFramework to not Map properties of a specific type(which is not my own type, I could not apply any attribute to a .Net's type).
Exception:
Sequence does not contains any element.
at System.Linq.Enumerable.First[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.ModelConfiguration.Edm.Services.StructuralTypeMappingGenerator.GetEntityTypeMappingInHierarchy(DbDatabaseMapping databaseMapping, EdmEntityType entityType)
at System.Data.Entity.ModelConfiguration.Edm.Services.AssociationTypeMappingGenerator.GenerateIndependentAssociationType(EdmAssociationType associationType, DbDatabaseMapping databaseMapping)
at System.Data.Entity.ModelConfiguration.Edm.Services.AssociationTypeMappingGenerator.Generate(EdmAssociationType associationType, DbDatabaseMapping databaseMapping)
at System.Data.Entity.ModelConfiguration.Edm.Services.DatabaseMappingGenerator.GenerateAssociationTypes(EdmModel model, DbDatabaseMapping databaseMapping)
at System.Data.Entity.ModelConfiguration.Edm.Services.DatabaseMappingGenerator.Generate(EdmModel model)
at System.Data.Entity.ModelConfiguration.Edm.EdmModelExtensions.GenerateDatabaseMapping(EdmModel model, DbProviderManifest providerManifest)
at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest, DbProviderInfo providerInfo)
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.GetEnumerator()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.Generic.IEnumerable<TResult>.GetEnumerator()
You can use the Ignore
method of DbModelBuilder
to exclude a type from being mapped.
public class MyContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Ignore<PropertyChangedEventHandler>();
}
}
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