c#中如何进行模糊查询？

https://blog.csdn.net/weixin_42974146/article/details/116355412

1.转载自：https://www.cnblogs.com/lgx5/p/7544681.html
针对DataGridView中已进行过数据绑定，即已向DataGridView中添加了一些数据，可以结合Linq查询，并让匹配查询的行高亮显示。

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Windows.Forms;  

namespace Maxes_PC_Client

{

public partial class frmWelcome : Form

{

private int beforeMatchedRowIndex = 0;


    <span class="token keyword">public</span> <span class="token function">frmWelcome</span><span class="token punctuation">(</span><span class="token punctuation">)</span>  
    <span class="token punctuation">{<!-- --></span>  
        <span class="token function">InitializeComponent</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
    <span class="token punctuation">}</span>  

    <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">frmWelcome_Load</span><span class="token punctuation">(</span><span class="token keyword">object</span> sender<span class="token punctuation">,</span> <span class="token class-name">EventArgs</span> e<span class="token punctuation">)</span>
   <span class="token punctuation">{<!-- --></span>  
        <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">dataGridViewInit</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
    <span class="token punctuation">}</span>  

    <span class="token comment">/// &lt;summary&gt;  </span>
    <span class="token comment">/// DataGridView添加数据、初始化  </span>
    <span class="token comment">/// &lt;/summary&gt;  </span>
    <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">dataGridViewInit</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
   <span class="token punctuation">{<!-- --></span>  
        Dictionary<span class="token operator">&lt;</span>String<span class="token punctuation">,</span> String<span class="token operator">&gt;</span> map <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token generic-method"><span class="token function">Dictionary</span><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
        map<span class="token punctuation">.</span><span class="token function">Add</span><span class="token punctuation">(</span><span class="token string">"Lily"</span><span class="token punctuation">,</span> <span class="token string">"22"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
        map<span class="token punctuation">.</span><span class="token function">Add</span><span class="token punctuation">(</span><span class="token string">"Andy"</span><span class="token punctuation">,</span> <span class="token string">"25"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
        map<span class="token punctuation">.</span><span class="token function">Add</span><span class="token punctuation">(</span><span class="token string">"Peter"</span><span class="token punctuation">,</span> <span class="token string">"24"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  

        <span class="token comment">// 在这里必须创建一个BindIngSource对象，用该对象接收Dictionary&lt;T, K&gt;泛型集合的对象  </span>
        <span class="token class-name">BindingSource</span> bindingSource <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">BindingSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
        <span class="token comment">// 将泛型集合对象的值赋给BindingSourc对象的数据源  </span>
        bindingSource<span class="token punctuation">.</span>DataSource <span class="token operator">=</span> map<span class="token punctuation">;</span>  

        <span class="token keyword">this</span><span class="token punctuation">.</span>dataGridView<span class="token punctuation">.</span>DataSource <span class="token operator">=</span> bindingSource<span class="token punctuation">;</span>  
    <span class="token punctuation">}</span>  

    <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">SearchButton_Click</span><span class="token punctuation">(</span><span class="token keyword">object</span> sender<span class="token punctuation">,</span> <span class="token class-name">EventArgs</span> e<span class="token punctuation">)</span> 
    <span class="token punctuation">{<!-- --></span>  
        <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>KeyWord<span class="token punctuation">.</span>Text<span class="token punctuation">.</span><span class="token function">Equals</span><span class="token punctuation">(</span><span class="token string">""</span><span class="token punctuation">)</span><span class="token punctuation">)</span> 
       <span class="token punctuation">{<!-- --></span>  
            <span class="token keyword">return</span><span class="token punctuation">;</span>  
        <span class="token punctuation">}</span>  

        <span class="token comment">// Linq模糊查询  </span>
        IEnumerable<span class="token operator">&lt;</span>DataGridViewRow<span class="token operator">&gt;</span> enumerableList <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>dataGridView<span class="token punctuation">.</span>Rows<span class="token punctuation">.</span><span class="token generic-method"><span class="token function">Cast</span><span class="token punctuation">&lt;</span><span class="token class-name">DataGridViewRow</span><span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  
        List<span class="token operator">&lt;</span>DataGridViewRow<span class="token operator">&gt;</span> list <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">from</span> item <span class="token keyword">in</span> enumerableList  
                                      <span class="token keyword">where</span> item<span class="token punctuation">.</span>Cells<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">.</span>Value<span class="token punctuation">.</span><span class="token function">ToString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">IndexOf</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>KeyWord<span class="token punctuation">.</span>Text<span class="token punctuation">)</span> <span class="token operator">&gt;=</span> <span class="token number">0</span>  
                                      <span class="token keyword">select</span> item<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">ToList</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>  

        <span class="token comment">// 恢复之前行的背景颜色为默认的白色背景  </span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>dataGridView<span class="token punctuation">.</span>Rows<span class="token punctuation">[</span>beforeMatchedRowIndex<span class="token punctuation">]</span><span class="token punctuation">.</span>DefaultCellStyle<span class="token punctuation">.</span>BackColor <span class="token operator">=</span> System<span class="token punctuation">.</span>Drawing<span class="token punctuation">.</span>Color<span class="token punctuation">.</span>White<span class="token punctuation">;</span>  

        <span class="token keyword">if</span> <span class="token punctuation">(</span>list<span class="token punctuation">.</span>Count <span class="token operator">&gt;</span> <span class="token number">0</span><span class="token punctuation">)</span>
       <span class="token punctuation">{<!-- --></span>  
            <span class="token comment">// 查找匹配行高亮显示  </span>
            <span class="token keyword">int</span> matchedRowIndex <span class="token operator">=</span> list<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">.</span>Index<span class="token punctuation">;</span>  
            <span class="token keyword">this</span><span class="token punctuation">.</span>dataGridView<span class="token punctuation">.</span>Rows<span class="token punctuation">[</span>matchedRowIndex<span class="token punctuation">]</span><span class="token punctuation">.</span>DefaultCellStyle<span class="token punctuation">.</span>BackColor <span class="token operator">=</span> System<span class="token punctuation">.</span>Drawing<span class="token punctuation">.</span>Color<span class="token punctuation">.</span>Yellow<span class="token punctuation">;</span>  
            <span class="token keyword">this</span><span class="token punctuation">.</span>beforeMatchedRowIndex <span class="token operator">=</span> matchedRowIndex<span class="token punctuation">;</span>  
        <span class="token punctuation">}</span>  
    <span class="token punctuation">}</span>  
<span class="token punctuation">}</span>  



}


  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65

2.转载自https://www.cnblogs.com/cqj98k/p/10573030.html
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; }
        }

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7

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" }
            };

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9

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();

  • 1

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();

  • 1

方法三：

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

  • 1

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
【推广】 免费学中医，健康全家人
原文地址：https://www.cnblogs.com/sunny3158/p/14978770.html