c# - 从 EF 6.0 Beta 升级到 RC 后出现 System.MissingMethodException

Question

这是什么意思？

System.MissingMethodException was unhandled by user code
HResult=-2146233069 Message=Method not found: 'System.Data.Entity.ModelConfiguration.Configuration.PrimitivePropertyConfiguration System.Data.Entity.ModelConfiguration.Configuration.StructuralTypeConfiguration1.Property(System.Linq.Expressions.Expression12<!0,!!0>>)'. Source=Att.Uds.DataLayerMappings StackTrace: at Att.Uds.DataLayerMappings.ItemTypeItemConfiguration..ctor() at Att.Uds.DataLayerMappings.UdsContext.OnModelCreating(DbModelBuilder modelBuilder) in c:\TFS\ATS-MSDev\UDS\Dev\Code\Att.Uds.DataLayerMappings\UdsContext.cs:line 163 at System.Data.Entity.DbContext.CallOnModelCreating(DbModelBuilder modelBuilder) at System.Data.Entity.Internal.LazyInternalContext.CreateModelBuilder() at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext) at System.Data.Entity.Internal.RetryLazy2.GetValue(TInput input) InnerException:

错误发生在这个类上:

namespace Contoso.Fabrikam.DataLayerMappings
{ 
  public abstract class NamedEntityConfiguration<TEntity> : EntityBaseConfiguration<TEntity> where TEntity : NamedEntity
  {
    public ConfigurationColumn NameColumn;
    protected new int LastOrdinalPosition
    {
      get
      {
        return (NameColumn.Ordinal);
      }
    }
    public NamedEntityConfiguration() <=== EXCEPTION HERE
    {
      NameColumn = new ConfigurationColumn() { Ordinal = base.LastOrdinalPosition+1, Name = "Name", IsRequired = true, Length = 128 };
      this.Property(t => t.Name)
        .HasColumnName(NameColumn.Name)
        .HasColumnOrder(NameColumn.Ordinal)
        .HasMaxLength(NameColumn.Length);
      if(NameColumn.IsRequired)
      {
        this.Property(t => t.Name).IsRequired();
      }
    }
  }
}

谢谢

Answer 1

@Saber 他的回答之所以有效，是因为当您将项目升级到更高的 .NET 版本时，项目文件不会自动升级。例如，如果您从 .NET 4.0 升级到 .NET 4.5 并编辑项目文件，您可能会看到以下内容:

<Reference Include="EntityFramework">
      <HintPath>..\packages\EntityFramework.6.1.3\lib\net40\EntityFramework.dll</HintPath>
    </Reference>
    <Reference Include="EntityFramework.SqlServer">
      <HintPath>..\packages\EntityFramework.6.1.3\lib\net40\EntityFramework.SqlServer.dll</HintPath>
    </Reference>

您必须将引用更改为 net45 而不是 net40。删除包时，这将产生相同的行为。