Question

我按照以下链接中的教程在网页上实现了排序，过滤和分页

https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/sort-filter-page?view=aspnetcore-2.2

排序和分页工作正常，但搜索功能出现问题。我收到错误“无法将类型'System.Linq.IQueryable'隐式转换为'System.Linq.IOrderedQueryable'”。有谁可以帮助我吗。预先感谢

我在这里有我的Model.Profile

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这是我的控制器上的代码抛出错误

public partial class Profile
{
    public Profile()
    {
        Assessment = new HashSet<Assessment>();

    }

    public int ProfileId { get; set; }
    [DisplayName ("Profile Name")]
    public string ProfileName { get; set; }
    [DisplayName("Company Name")]
    public string CompanyName { get; set; }
    public int RoleId { get; set; }
    public int IndustryId { get; set; }
    public int PerspectiveId { get; set; }
    public int InfluenceLevelId { get; set; }
    public int OwnershipLevelId { get; set; }
    public string Interviewer { get; set; }
    [DisplayName ("Date Interviewed")]
    public DateTime? DateInterviewed { get; set; }
    [DisplayName("Created By")]
    public string CreatedBy { get; set; }
    [DisplayName("Created Date")]
    public DateTime? CreatedDate { get; set; }
    [DisplayName("Modified By")]
    public string ModifiedBy { get; set; }
    [DisplayName("Modifed Date")]
    public DateTime? ModifiedDate { get; set; }

    public virtual Industry Industry { get; set; }
    [DisplayName ("Influence Level")]
    public virtual InfluenceLevel InfluenceLevel { get; set; }
    [DisplayName ("Ownership Level")]
    public virtual OwnershipLevel OwnershipLevel { get; set; }
    public virtual Perspective Perspective { get; set; }
    public virtual Role Role { get; set; }
    public virtual ICollection<Assessment> Assessment { get; set; }
}
}

Answer 1

变量配置文件已经声明为IOrderedQueryable，并且您尝试分配IQueryable。

如果尝试会怎样：

if (!string.IsNullOrEmpty (searchData)) {

    var profile2 = profile.Where (p =>
        p.ProfileName.Contains (searchData)); //Here is the error

}

Answer 2

应该是一个简单的解决方案。使用LINQ时，可以使用.ToList()方法。因此，对于您的代码：

var profile = _context.Profile
    .Include (p => p.Industry)
    .Include (p => p.InfluenceLevel)
    .Include (p => p.OwnershipLevel)
    .Include (p => p.Perspective)
    .Include (p => p.Role)
    .OrderByDescending (p => p.ProfileName)
    .ToList(); // add here

if (!string.IsNullOrEmpty (searchData)) {

    profile = profile.Where (p =>
        p.ProfileName.Contains (searchData)).ToList(); // add here

}

我创建了一个DotNetFiddle，向您展示了我刚才写的一个示例。它按预期工作。

让我知道这是否可行。

Answer 3

首先获得IOrderedQueryable类型的profile，然后为其分配IQueryable类型的日期profile.Where (p =>p.ProfileName.Contains (searchData));。

尝试使用以下代码将profile设置为IQueryable：

var profile = from p in _context.Profile
              select p;

 if (!string.IsNullOrEmpty (searchData)) {

    profile = profile
       .Include (p => p.Industry)
       .Include (p => p.InfluenceLevel)
       .Include (p => p.OwnershipLevel)
       .Include (p => p.Perspective)
       .Include (p => p.Role)
       .OrderByDescending (p => p.ProfileName)
       .Where (p =>p.ProfileName.Contains (searchData));

}

Answer 4

谢谢邹兴！

昨天，我还尝试在数据集上添加IQueryable，如下所示，它可以正常工作。当我看到您的答案时，我尝试了一下，它也正在起作用。感谢您的帮助，这两个实现工作正常：）

        IQueryable<Profile> profile = _context.Profile
            .Include(p => p.Industry)
            .Include(p => p.InfluenceLevel)
            .Include(p => p.OwnershipLevel)
            .Include(p => p.Perspective)
            .Include(p => p.Role)
            .OrderByDescending(p => p.ProfileName);


        if (!string.IsNullOrEmpty(searchData))
        {

            profile = profile.Where(p => p.ProfileName.Contains(searchData));

        }

无法将类型'System.Linq.IQueryable <models.profile>'隐式转换为'System.Linq.IOrderedQueryable <models.profile>'

4 个答案: