mapping private property entity framework code fir

问题:

I am using EF 4.1 and was look for a nice workaround for the lack of enum support. A backing property of int seems logical.

    [Required]
    public VenueType Type
    {
        get { return (VenueType) TypeId; }
        set { TypeId = (int) value; }
    }

    private int TypeId { get; set; }

But how can I make this property private and still map it. In other words:

How can I map a private property using EF 4.1 code first?

回答1:

you can't map private properties in EF code first. You can try it changing it in to protected and configuring it in a class inherited from EntityConfiguration .
Edit
Now it is changed , See this https://stackoverflow.com/a/13810766/861716

回答2:

Here's a convention you can use in EF 6+ to map selected non-public properties (just add the [Column] attribute to a property).

In your case, you'd change TypeId to:

    [Column]
    private int TypeId { get; set; }

In your DbContext.OnModelCreating, you'll need to register the convention:

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Add(new NonPublicColumnAttributeConvention());
    }

Finally, here's the convention:

/// <summary>
/// Convention to support binding private or protected properties to EF columns.
/// </summary>
public sealed class NonPublicColumnAttributeConvention : Convention
{

    public NonPublicColumnAttributeConvention()
    {
        Types().Having(NonPublicProperties)
               .Configure((config, properties) =>
                          {
                              foreach (PropertyInfo prop in properties)
                              {
                                  config.Property(prop);
                              }
                          });
    }

    private IEnumerable<PropertyInfo> NonPublicProperties(Type type)
    {
        var matchingProperties = type.GetProperties(BindingFlags.SetProperty | BindingFlags.GetProperty | BindingFlags.NonPublic | BindingFlags.Instance)
                                     .Where(propInfo => propInfo.GetCustomAttributes(typeof(ColumnAttribute), true).Length > 0)
                                     .ToArray();
        return matchingProperties.Length == 0 ? null : matchingProperties;
    }
}

回答3:

Another workaround might be to set your field as internal:

    [NotMapped]
    public dynamic FacebookMetadata {
        get
        {
            return JObject.Parse(this.FacebookMetadataDb);
        }
        set
        {
            this.FacebookMetadataDb = JsonConvert.SerializeObject(value);
        }
    }

    ///this one
    internal string FacebookMetadataDb { get; set; }

and add it to tour model:

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<System.Data.Entity.ModelConfiguration.Conventions.ManyToManyCascadeDeleteConvention>();

        ///here
        modelBuilder.Entity<FacebookPage>().Property(p => p.FacebookMetadataDb);

        base.OnModelCreating(modelBuilder);
    }

回答4:

Extending @crimbo's answer above ( https://stackoverflow.com/a/21686896/3264286 ), here's my change to include public properties with private getters:

private IEnumerable<PropertyInfo> NonPublicProperties(Type type)
{
    var matchingProperties = type.GetProperties(BindingFlags.SetProperty | BindingFlags.GetProperty | BindingFlags.NonPublic | BindingFlags.Instance)
                                 .Where(propInfo => propInfo.GetCustomAttributes(typeof(ColumnAttribute), true).Length > 0)
                                 .Union(
                                        type.GetProperties(BindingFlags.SetProperty | BindingFlags.GetProperty | BindingFlags.Public | BindingFlags.Instance)
                                            .Where(propInfo => propInfo.GetCustomAttributes(typeof(ColumnAttribute), true).Length > 0
                                                               && propInfo.GetGetMethod().IsNull())
                                  )
                                 .ToArray();
    return matchingProperties.Length == 0 ? null : matchingProperties;
}

回答5:

Another way to handle this is to defines a custom entity configuration and add a binding for that.

In your class add a class that inherits from EntityTypeConfiguration (This can be found in System.Data.Entity.ModelConfiguration)

public partial class Report : Entity<int>
    {
        //Has to be a property
        private string _Tags {get; set;}

        [NotMapped]
        public string[] Tags
        {
            get => _Tags == null ? null : JsonConvert.DeserializeObject<string[]>(_Tags);
            set => _Tags = JsonConvert.SerializeObject(value);
        }

        [MaxLength(100)]
        public string Name { get; set; }

        [MaxLength(250)]
        public string Summary { get; set; }

        public string JsonData { get; set; }

        public class ReportConfiguration: EntityTypeConfiguration<Report>
        {
            public ReportConfiguration()
            {
                Property(p => p._tags).HasColumnName("Tags");
            }
        }
    }

In your context add the following:

using Models.ReportBuilder;
public partial class ReportBuilderContext:DbContext
{
    public DbSet<Report> Reports { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new Report.ReportConfiguration());
        base.OnModelCreating(modelBuilder);
    }
}

Wish I could say I found this on my own, but I stumbled upon it here:https://romiller.com/2012/10/01/mapping-to-private-properties-with-code-first/

回答6:

As seen in your model you grant read access to the property. So maybe you want to block set access and map to EF using a private setter. Like this.

[Required]
private int TypeId { get; private set; }