C＃SQL linq查询错误 [英] C# SQL linq query error

问题描述

亲爱的专家;

我正在使用实体框架，sql数据库在c＃windows应用程序项目上工作，我正在创建winform（打开表单）来搜索成员并获得结果devexpress gridcontrol put表单有很多搜索字段可以按名称，代码，IP，日期，公司，品牌，模型和一些单选按钮进行搜索我需要使用linq查询代码来查找所有字段的成员过滤器，如果有一个或多个空忽略过滤器和得到所有其他选择成员与过滤器



这是一个示例代码，但我需要它所有字段类型（复选框，无线电，字符串，整数，日期，查找和组合框）



我尝试过：

Dear experts ;
i'm work on c# windows application project using entity framework , sql database and i'm create winform (open form)to search about members and get result in devexpress gridcontrol put the form have many search fields can search by name , code , ip , date from to ,company , brand , model and some radio buttons i need code using linq query to find the members filter by all fields if one or more empty ignore filter and get all else select members with filter

this is a sample code but i need it for all fields type (checkbox , radio ,string ,int ,date ,lookup and combobox)

What I have tried:

string query = "select * from Members where (@name is null or MemberName = @name) and (@code is null or MemberCode = @code)";
var data = db.Members.SqlQuery(query, new SqlParameter("@name", Name), new SqlParameter("@code", code));
memberBindingSource.DataSource = data.ToList(); </pre

推荐答案

Hello Wessam，

您可以使用以下LINQ查询

Hello Wessam,
You can use below LINQ query

var query = from d in db.Members select d;
//Filter the result based on value passed by user for Member Name
if (!string.IsNullOrEmpty(memName))
    query = query.Where(m => m.MemberName == memName);
//Filter for Member Code
if (!string.IsNullOrEmpty(memCode))
    query = query.Where(m => m.MemberCode == memCode);

//Final query execution
var memberList = query.ToList();

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