用于创建具有内部Collection的谓词的动态查询

Question

我正在为我的MVC EF应用程序创建搜索功能.我正在使用动态查询创建它.并遵循此方法https://www.codeproject.com/Articles/493917/Dynamic-Querying-with-LINQ-to-Entities-and-Express

它用于创建实体的谓词bool和string字段.我的应用程序中的主要实体是Applicant

EDMX Applicant正在关注

     public partial class Applicant
    {

      public Applicant()
       {
         this.ApplicantEducations = new HashSet<ApplicantEducation>();
         this.ApplicantSkills = new HashSet<ApplicantSkill>();
         this.Applications = new HashSet<Application>();
         this.Experiences = new HashSet<Experience>();
        }

    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public byte[] CV_Upload1 { get; set; }
    public string CV_Upload2 { get; set; }
    public string email { get; set; }
    public string password { get; set; }
    public Nullable<System.DateTime> DOB { get; set; }

   virtual ICollection<ApplicantEducation> ApplicantEducations { get; set; }
   virtual ICollection<ApplicantSkill> ApplicantSkills { get; set; }
   virtual ICollection<Application> Applications { get; set; }
   virtual ICollection<Experience> Experiences { get; set; }
}

我想搜索,即在申请人类型学院的教育中提交的机构名称.申请人可以拥有一个或多个ApplicantEducations对象.

以下是我的申请人教育的EDMX课程

   public partial class ApplicantEducation
{
    public int id { get; set; }
    public Nullable<int> ApplicantId { get; set; }
    public Nullable<int> InstituteId { get; set; }
    public Nullable<int> EducationLevelId { get; set; }
    public Nullable<bool> IsComplete { get; set; }
    public Nullable<System.DateTime> DateStart { get; set; }
    public Nullable<System.DateTime> DateEnd { get; set; }
    public Nullable<short> GPA { get; set; }

    public virtual EducationLevel EducationLevel { get; set; }
    public virtual Institute Institute { get; set; }
    public virtual Applicant Applicant { get; set; }
}

我的学院实体课就是这样的

public class Institute
  {
         public int Id { get; set; }
         public string Name { get; set; }

  }

因此,用户将通过指定学院名称进行搜索,所有申请人将通过该学院的教育进行检索.

正如我上面提到的链接.下面举例说明字符串字段谓词构建

     private static Expression<Func<TDbType, bool>> ApplyStringCriterion<TDbType,
        TSearchCriteria>(TSearchCriteria searchCriteria, PropertyInfo searchCriterionPropertyInfo,
        Type dbType, MemberInfo dbFieldMemberInfo, Expression<Func<TDbType, bool>> predicate)
    {
        // Check if a search criterion was provided
        var searchString = searchCriterionPropertyInfo.GetValue(searchCriteria) as string;
        if (string.IsNullOrWhiteSpace(searchString))
        {
            return predicate;
        }
        // Then "and" it to the predicate.
        // e.g. predicate = predicate.And(x => x.firstName.Contains(searchCriterion.FirstName)); ...
        // Create an "x" as TDbType
        var dbTypeParameter = Expression.Parameter(dbType, @"x");
        // Get at x.firstName
        var dbFieldMember = Expression.MakeMemberAccess(dbTypeParameter, dbFieldMemberInfo);
        // Create the criterion as a constant
        var criterionConstant = new Expression[] { Expression.Constant(searchString) };
        // Create the MethodCallExpression like x.firstName.Contains(criterion)
        var containsCall = Expression.Call(dbFieldMember, StringContainsMethod, criterionConstant);
        // Create a lambda like x => x.firstName.Contains(criterion)
        var lambda = Expression.Lambda(containsCall, dbTypeParameter) as Expression<Func<TDbType, bool>>;
        // Apply!
        return predicate.And(lambda);
    }

上面的代码用于构建主实体类(申请人)中包含的简单字符串字段的谓词.但申请人也有ApplicantEducation集合,所以我的问题是如何为where子句(方法)创建动态查询(谓词),linq这样当用户搜索学院名称时,所有申请人都将获得相同的教育.

我的搜索条件如下,

  public class SearchCriteriaVM
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime? DOB { get; set; }     
    public string Description { get; set; }

    public ICollection<Models.ApplicantEducationVM> ApplicantEducations { get; set; }
    public ICollection<Models.ExperienceVM> Experiences { get; set; }
    public ICollection<Models.ApplicantSkillsVM> ApplicantSkills { get; set; }

    public ICollection<Models.ApplicationsVM> Applications { get; set; }



}

我有点失落,这怎么可能.

谢谢