c# - 如何使用 LINQ 进行累积搜索

Question

如果我想搜索req_ser ,req_year .. ,so on fields

我执行以下操作：

            if (obj.RequestSerial != 0)
            {
                if (condition != "")
                    condition = condition + " AND ";

                condition += " req_ser= " + obj.RequestSerial;
            }

            if (obj.RequestYear != 0)
            {
                if (condition != "")
                    condition = condition + " AND ";

                condition += " req_year = " + obj.RequestYear;
            }

然后在我的选择语句中，我执行以下操作：

SELECT * FROM .... WHERE ..... + condition 

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如何使用与 LINQ TO SQL 实体相同的概念进行搜索？

Answer 1

你可以用同样的逻辑来做......

var query = DB.MyItems;

if(conditionA != 0)
    query = query.Where(x => x.A == conditionA);

if(conditionB != 0)
    query = query.Where(x => x.B == conditionB);

var items = query.ToList();

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使用您问题中的属性，您的代码可能如下所示：

var query = DB.MyItems;//I don't know what you table it called

if(obj.RequestSerial != 0)
    query = query.Where(x => x.req_ser == obj.RequestSerial);

if(obj.RequestYear != 0)
    query = query.Where(x => x.req_year== obj.RequestYear);

var items = query.ToList();