LINQ查詢裏面關於ArrayIndex

Question

我有LINQ表達式節點類型ArrayIndex沒有在LINQ支載到實體錯誤，當我嘗試做以下

public List<AttachmentList> ShowAttachments(int type, int ReferenceId) 
{ 

    try 
    { 
     var attachmentNames = 
      (from attachment in tent.Attachments 
       where (attachment.Attachment_Type == type 
        && attachment.Attachment_Reference_Pk == ReferenceId) 
       select new AttachmentList 
         { 
          Attachment_Pk = attachment.Attachment_Pk, 
          Attachment_File_Path = attachment 
           .Attachment_File_Path.Split(new[] {'$'})[1] 
         }).ToList(); 

     return attachmentNames; 
    } 
    catch (Exception ex) 
    { 
     ExceptionHandler.ExceptionLog(ex); 
     return null; 
    } 
} 

正如你可以看到，我試圖分裂Attachmentfilepath其中包含'$'並指定第二個值（[1]）到Attachment_FilePath

任何人都可以請建議我怎麼可以分割並且在相同的查詢賦值給AttachmentList串 感謝

Answer 1

說實話，最簡單的方法是在客戶端進行分割，除非你真的需要它是一個完整的實體。例如：

var query = from attachment in tent.Attachments 
      where attachment.Attachment_Type == type && 
        attachment.Attachment_Reference_Pk == ReferenceId 
      select new { Attachment_Pk, Attachment_File_Path }; 

// Force the rest to execute client-side. 
var attachmentNames = query.AsEnumerable() 
          .Select(x => new AttachmentList { 
           Attachment_Pk = x.Attachment_Pk, 
           Attachment_File_Path = x.Attachment_File_Path 
                 .Split('$')[1] 
          }) 
          .ToList(); 

Answer 2

可以投射到一個匿名類首先要抓住你所需要的數據，然後切換到使用LINQ to對象，其中這種操作支持使用AsEnumerable()：

var attachmentNames = (from attachment in tent.Attachments 
         where (attachment.Attachment_Type == type && attachment.Attachment_Reference_Pk == ReferenceId) 
         select new { attachment.Attachment_Pk, attachment.Attachment_File_Path }) 
         .AsEnumerable() 
         .Select(attachment => 
         new AttachmentList 
         { 
          Attachment_Pk = attachment.Attachment_Pk, 
          Attachment_File_Path = attachment.Attachment_File_Path.Split(new[] { '$' })[1] 
         }).ToList();