使用EntityCollection.Add（）EF 4.1时出错

Question

我正在尝试将一个代理实体（一个联系人）添加到另一个代理实体（客户）的集合属性中。第collectionProperty.Add(entityModel);行给出了错误

'System.Data.Objects.DataClasses.EntityCollection.Add（HTS.Models.Contact）'的最佳重载方法匹配' 有一些无效的论点

我在这里做错了什么？

public dynamic AddNew(
    Type entityType,
    string modelParentType,
    int? modelParentId,
    string collectionName
    )
{
    var parentType = Type.GetType("HTS.Models." + modelParentType);
    var parentModel = Set(parentType).Find(modelParentId);
    Set(parentType).Attach(parentModel);

    var entityModel = Set(entityType).Create();

    //var foreignKeyProperty = entityType.GetProperty(modelParentType + "Id");
    //if (foreignKeyProperty != null)
    //{
    //  foreignKeyProperty.SetValue(entityModel, modelParentId, null);
    //}

    var collectionProperty = (dynamic)parentType
                            .GetProperty(collectionName)
                            .GetValue(parentModel, null);
    collectionProperty.Add(entityModel);

    SaveChanges();
    return entityModel;
}

用于生成错误的模型 - 请原谅所有注释，我还在学习。

public class Contact : SocialEntity {
    public Contact() { Bag["DisplayName"] = "Contact"; }
    [UIHint("hidden")]
    public virtual int? CustomerId { get; set; }
    [UIHint("NoEdit ManyToMany")]
    public virtual ICollection<Customer> Customers { get; set; }
}
public class Customer : SocialEntity {
    public Customer() { Bag["DisplayName"] = "Customer"; }
    [Display(Name="Contacts", ShortName="Contact")] [UIHint("ManyToMany")]
    public virtual ICollection<Contact> Contacts { get; set; }
    //[Display(Name="Sales")] [UIHint("NoEdit")]
    //public virtual ICollection<Sale> Sales { get; set; }
}
public class SocialEntity : BaseEntity {
    [Display(Name="Name")]
    public virtual string Name { get; set; }
    [Display(Name="Addresses",ShortName="Address")]
    public virtual ICollection<Address> Addresses { get; set; }
    [Display(Name="PhoneNumbers",ShortName="PhoneNumber")]
    public virtual ICollection<PhoneNumber> PhoneNumbers { get; set; }
    [Display(Name="EmailAddresses",ShortName="EmailAddress")]
    public virtual ICollection<EmailAddress> EmailAddresses { get; set; }
}
public class BaseEntity : Base { }
public class Base
{
    public Base()
    {
        TypeName = this.GetType().BaseType.Name;
        //EntityState = 16;
    Bag = new Dictionary<string,string>();
    Bag["AlignRight"] = "AlignRight";
        Bag["DisplayName"] = "";
    }
    [UIHint("hidden")] [Display(Name="Id")]
    public virtual int Id { get; set; }
    [ScaffoldColumn(false)]
    public virtual string empty { get; set; }
    [NotMapped] [UIHint("hidden")]
    public virtual string TypeName { get; set; }
    [NotMapped] [UIHint("hidden")]
    public virtual int? EntityState { get; set; }
    [NotMapped] [ScaffoldColumn(false)]
    public virtual bool? IsSavable { get; set; }
    [NotMapped] [ScaffoldColumn(false)]
    public virtual bool? Visited { get; set; }
    [NotMapped]
    [ScaffoldColumn(false)]
    public virtual Dictionary<string,string> Bag { get; set; }
}

编辑：以下是调用AddNew()

的代码

public dynamic FindOrAddNew(
    string entityType,
    int? id,
    string modelParentType,
    int? modelParentId
    )
{
    var type = Type.GetType("HTS.Models." + entityType);
    var parentType = Type.GetType("HTS.Models." + modelParentType);
    dynamic entity = null;
    if (id != null)
    {
        entity = Set(type).Find(id);
    }
    else
    {
        string collectionName = "";
        ModelMetadata metadata = null;
        foreach (PropertyInfo prop in parentType.GetProperties())
        {
            metadata = ModelMetadataProviders.Current
                            .GetMetadataForProperty
                            (
                                null, parentType, prop.Name
                            );
            if (metadata.ShortDisplayName == entityType)
            {
                collectionName = prop.Name;
                if (metadata.TemplateHint != null
                    && metadata.TemplateHint.Contains("ManyToMany"))
                {
                    entity = AddNew(type, modelParentType, modelParentId, collectionName);
                }
                else
                {
                    entity = AddNew(type, modelParentType, modelParentId);
                }
                collectionName = "";
            }
        }
    }
    return entity;
}

编辑：以下是调用FindOrAddNew()

的代码

public ActionResult Edit(
    string responseType,
    string modelType,
    int? modelId,
    string modelPrefix,
    string modelParentType,
    int? modelParentId
    )
{
    if (modelType == null) // temporary initializer
    {
        modelType = "Customer";
        modelId = 1;
    }

    var entity = db.FindOrAddNew(modelType, modelId, modelParentType, modelParentId);
    SetSelectList(db, entity);

    if (responseType == "Partial")
    {
        ViewData.TemplateInfo.HtmlFieldPrefix = modelPrefix;
        ViewData["indexed"] = true;
        entity.IsSavable = false;
        return PartialView(entity);
    }
    else
    {
        entity.IsSavable = true;
        return View(entity);
    }
}

//SAVE
public void Save([ModelBinder(typeof(CustomModelBinder))] dynamic model)
{
    db.Update(model, null, "");
    db.SaveChanges();
}