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Visual Studio 2017 C# 我正在嘗試爲MySQL實施Linq2db,並且是一名Linq新手,有點麻煩。我試圖從GitHub linq2db中使用一個簡單的兩列表(maillist) - 整數列表和client_id,它們一起是主鍵。 我已經從nuget安裝了linq2db.MySql,包括linq2db和linq2db.t4models。使用「傳統」方法,我可以處理數據庫,以便連接起作用。這是我迄今爲止所做的。linq2db.MySql - 無法找到源類型的查詢模式的實現..找不到的地方
我的App.config:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7"/>
</startup>
<connectionStrings>
<add name="MyWinBroker" connectionString="Server=localhost;Port=3306;Database=winbroker;Uid=root;[email protected]!;charset=utf8;" providerName="MySql.Data.MySqlClient"/>
</connectionStrings>
</configuration>
POCO類:
using LinqToDB.Mapping;
using LinqToDB;
[Table(Name = "maillist")]
public class Mailing
{
[PrimaryKey, Identity]
public int List { get; set; }
public int Client_id { get; set; }
[Column(Name = "list"), NotNull]
public int MailList { get; set; }
[Column(Name = "client_id"), NotNull]
public int Client { get; set; }
}
public class DbWinbroker : LinqToDB.Data.DataConnection
{
public DbWinbroker() : base("MyWinbroker") { }
public ITable<Mailing> Mailing { get { return GetTable<Mailing>(); } }
}
查詢
using System;
using System.Windows.Forms;
using Microsoft.VisualBasic.FileIO;
using FileHelpers;
using FileHelpers.Events;
using Itenso.TimePeriod;
using MySql.Data.MySqlClient;
using LinqToDB;
using System.Collections.Generic;
public static List<Mailing> All()
{
using (var db = new DbWinbroker())
{
var query = from p in db.Mailing
where p.MailList < 99
select p;
return query.ToList();
}
}
這將無法編譯,我得到db.Mailing下的紅色波浪線在查詢和錯誤中:
Could not find an implementation of the query pattern for source type 'ITable<Form1.Mailing>'. 'Where' not found.
如果我刪除where子句,我會得到兩個不同的錯誤。 也許我需要包括一個參考,但哪個?
The type of the expression in the select clause is incorrect. Type inference failed in the call to 'Select'.
'T' does not contain a definition for 'ToList' and no extension method 'ToList' accepting a first argument of type 'T' could be found (are you missing a using directive or an assembly reference?)
我看過很多關於這個錯誤變化的文章,但我仍然不明白。 任何幫助,將不勝感激。
TIA, Gerry。