如何在一个查询中添加SqlMethods.Like()的变量计数? [英] How can I add variable count of SqlMethods.Like() in one query?

问题描述

接下来您能帮我吗:我想在一个查询中添加SqlMethods.Like()的变量计数?

Can you help me with next: I'd like to add variable count of SqlMethods.Like() in one query?

例如:我在目录catCode中有四个单词，如何使用四个SqlMethods.Like()创建LINQ查询?

For example: I've four words in list catCode, how can I create LINQ query with four SqlMethods.Like()?

using (var db = new MappingDataContext(_connection))
{
    db.ObjectTrackingEnabled = false;

    return (
        from r in db.U_CDW_REPORTs
        where (catCode.Length > 0 ? 
            SqlMethods.Like(r.CATEGORY, catCode) : r.CATEGORY != "*")
        where r.SI_QTY > 0
        orderby r.SI_QTY descending
        select new Item
        {
            ...
        }).ToList();
}

推荐答案

您需要的是对SqlMethod.Like操作进行动态或运算.您需要 PredicateBuilder .

What you need is dynamically OR-ing SqlMethod.Like operations. You need the PredicateBuilder.

---

更新:这是一个如何使用谓词生成器的示例.

---

Update: Here is an example of how to use the predicate builder.

string[] searchItems =
    new string[] { "Pattern1", "Pattern2", "Pattern3" };

var likeExpression = PredicateBuilder.False<U_CDW_REPORT>();

foreach (string searchItem in searchItems)
{
    var searchPattern = "%" + searchItem + "%";
    likeExpression = likeExpression.Or(r => 
        SqlMethods.Like(r.CATEGORY, searchPattern));
}

return (
    from r in db.U_CDW_REPORTs.Where(likeExpression)
    where r.SI_QTY > 0
    orderby r.SI_QTY descending
    select new Item { ... }).ToList();

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