[英]Select a specific column in LINQ web service with Entity Framework
我只想從包含列ID
, Name
, Gender
和MarkUp
的簡單表中從實體框架僅返回一個稱為Name
的列。
當我運行以下代碼時,出現以下錯誤:
無法將類型'System.Collections.Generic.List隱式轉換為'System.Collection.Generic.List'
碼:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Data;
using System.Data.SqlClient;
using SimpleWebApplication;
using System.Configuration;
namespace SimpleWebApplication
{
/// <summary>
/// Summary description for SimpleWebService
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class SimpleWebService : System.Web.Services.WebService
{
[WebMethod]
public List<tblStudent> getAllLINQ()
{
List<string> studentList = new List<string>();
try
{
using (TestingEntities database = new TestingEntities())
{
var studentData = (from table in database.tblStudents select table).Select(u => new { u.Name });
studentList = studentData.ToList();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
return studentList;
}
}
}
如果您只需要名稱,則僅選擇名稱。
var query = from table in database.tblStudents select Name;
並且您的列表應該是string
列表,因為名稱是字符串。
List<string> studentList = new List<string>();
您可以像這樣將結果分配給列表:
studentList = query.ToList();
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.