c#中如何使用到模糊查詢

c#中如何使用到模糊查詢,先舉個最簡單實用的例子，可在vs控制台應用程序中輸出：

定義實體類：

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

            public string Name { get; set; }

            public int? Age { get; set; }

            public string Sex { get; set; }
        }

 

為實體類賦值存放到集合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" }

            };

模糊查詢條件：根據Name=1或者Sex=女模糊查詢

   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();

   知識講解：

  1,Contains("key"),---意義等同於ql server中的like '%key%'，從兩端模糊匹配

  2,StartsWith("key"),---意義等同於sql server中的like 'key%',從開頭模糊匹配

  3,EndsWith("key"),---意義等同於sql server中的like '%key',從結尾模糊匹配

 

  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();

  知識講解：

  1，c.Name.IndexOf(key)>=0 ---意義等同於 like '%key%',從兩端模糊匹配

  2，c.Name.StartsWith(key) ---等同於like 'key%' ,從開頭模糊匹配

  3，c.Name.EndWith(key) ---等同於like '%key',從結尾模糊匹配

  vs控制台輸出打印代碼：

 

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