c#中如何使用到模糊查询

c#中如何使用到模糊查询,先举个最简单实用的例子，可在vs控制台应用程序中输出：

定义实体类：

 public class Student
        {
            public int ID { get; set; }

            public string Name { get; set; }

            public int? Age { get; set; }

            public string Sex { get; set; }
        }

 

为实体类赋值存放到集合list中：

 List<Student> lsStudent = new List<Student>(){
                new Student { ID = 1,Name = "1", Age = 128, Sex = null },
                new Student { ID = 2, Name = "2", Age = 18, Sex = "女" },
                new Student { ID = 3, Name = "31", Age = 13, Sex = "男" },
                new Student { ID = 4, Name = "4", Age = 23, Sex = "男" },
                new Student { ID = 5, Name = "51", Age = null, Sex = "女" },
                new Student { ID = 6, Name = "6", Age = null, Sex = "女" },
                new Student { ID = 7, Name = "7", Age = null, Sex = "女" }

            };

模糊查询条件：根据Name=1或者Sex=女模糊查询

   string key = "1";
   string sex = "女";

  方法一：linq

   List<Student> resultList = (from c in lsStudent where  c.Name.Contains(key) ||c.Sex.Contains(sex) select c).ToList();

  知识讲解：

  1,Contains("key"),---意义等同于ql server中的like '%key%'，从两端模糊匹配

  2,StartsWith("key"),---意义等同于sql server中的like 'key%',从开头模糊匹配

  3,EndsWith("key"),---意义等同于sql server中的like '%key',从结尾模糊匹配

 

 方法二：
   List<Student> resultList = lsStudent.Where(str => str.Name.Contains(key) || str.Sex.Contains(key)).ToList();

 

  方法三：
   List<Student> resultList = (from c in lsStudent where c.Name.IndexOf(key)>=0 ||c.Sex.IndexOf(sex)>=0 select c).ToList();

  知识讲解：

  1，c.Name.IndexOf(key)>=0 ---意义等同于 like '%key%',从两端模糊匹配

  2，c.Name.StartsWith(key) ---等同于like 'key%' ,从开头模糊匹配

  3，c.Name.EndWith(key) ---等同于like '%key',从结尾模糊匹配

  vs控制台输出打印代码：

 

  string json = JsonConvert.SerializeObject(resultList, Newtonsoft.Json.Formatting.Indented);
  Console.WriteLine(json);