C# LINQ 查詢報(bào)錯(cuò):指定的轉(zhuǎn)換無(wú)效
using System; using System.Collections; using System.Collections.Generic; using System.ComponentModel; using System.Dynamic; using System.Linq; using System.Runtime.CompilerServices; using System.Data.Linq; using System.Data.Linq.Mapping; using System.Xml; using System.Runtime.Remoting.Contexts; namespace ConsoleApp3_Test { internal class Aa { static void Main(string[] args) { DataContext dataContext = new DataContext("server=192.168.1.1,12345;database=test;uid=sa;pwd=111"); Table<User> Users=dataContext.GetTable<User>(); User query = (from user in Users where user.name.Contains("王") select user ). First(); Console.WriteLine(query.name); } } [Table (Name = "c_user")] public class User { [Column(Name = "userid",IsPrimaryKey =true)] public int ID; //此處的字段類型錯(cuò)誤,數(shù)據(jù)庫(kù)中該字段類型為varchar [Column (Name = "username")] public string name; } }

原因:
實(shí)體類的字段(ID)的類型與數(shù)據(jù)庫(kù)中的類型不一致。實(shí)體類的ID類型為int,數(shù)據(jù)庫(kù)中的類型為varchar。將實(shí)體類中ID字段類型改為string 即可。

浙公網(wǎng)安備 33010602011771號(hào)