C# n其他人！非常感谢。实际上，我应该注意到，我个人不能将IsSqlLikeMatch的实现归功于我。几年前在互联网上找到的。我能找到的最好的归属是：我认为那是原创的 List<string> list = new List<string&g

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n其他人！非常感谢。实际上，我应该注意到，我个人不能将IsSqlLikeMatch的实现归功于我。几年前在互联网上找到的。我能找到的最好的归属是：我认为那是原创的

List<string> list = new List<string>();
list.Add("line one");
list.Add("line two");
list.Add("line three");
list.Add("line four");
list.Add("line five");
list.Add("line six");
list.Add("line seven");
list.Add("line eight");
list.Add("line nine");
list.Add("line ten");

string pattern = "%ine%e";

var res = from i in list
            where System.Data.Linq.SqlClient.SqlMethods.Like(i, pattern)
              select i;

public static bool IsSqlLikeMatch(string input, string pattern)
{
   /* Turn "off" all regular expression related syntax in
    * the pattern string. */
   pattern = Regex.Escape(pattern);

   /* Replace the SQL LIKE wildcard metacharacters with the
    * equivalent regular expression metacharacters. */
   pattern = pattern.Replace("%", ".*?").Replace("_", ".");

   /* The previous call to Regex.Escape actually turned off
    * too many metacharacters, i.e. those which are recognized by
    * both the regular expression engine and the SQL LIKE
    * statement ([...] and [^...]). Those metacharacters have
    * to be manually unescaped here. */
   pattern = pattern.Replace(@"\[", "[").Replace(@"\]", "]").Replace(@"\^", "^");

   return Regex.IsMatch(input, pattern, RegexOptions.IgnoreCase);
}

public static IEnumerable<T> Like<T>(this IEnumerable<T> source, Func<T, string> selector, string pattern)
{
   return source.Where(t => IsSqlLikeMatch(selector(t), pattern));
}

string pattern = "%ine%e";
var res = list.Like(s => s, pattern);

public static class LikeExtension
{
    public static IEnumerable<T> Like<T>(this IEnumerable<T> source, Func<T, string> selector, string pattern)
    {
        var regex = new Regex(ConvertLikeToRegex(pattern), RegexOptions.IgnoreCase);
        return source.Where(t => IsRegexMatch(selector(t), regex));
    }

    static bool IsRegexMatch(string input, Regex regex)
    {
        if (input == null)
            return false;

        return regex.IsMatch(input);
    }

    static string ConvertLikeToRegex(string pattern)
    {
        StringBuilder builder = new StringBuilder();
        // Turn "off" all regular expression related syntax in the pattern string
        // and add regex begining of and end of line tokens so '%abc' and 'abc%' work as expected
        builder.Append("^").Append(Regex.Escape(pattern)).Append("$");

        /* Replace the SQL LIKE wildcard metacharacters with the
        * equivalent regular expression metacharacters. */
        builder.Replace("%", ".*").Replace("_", ".");

        /* The previous call to Regex.Escape actually turned off
        * too many metacharacters, i.e. those which are recognized by
        * both the regular expression engine and the SQL LIKE
        * statement ([...] and [^...]). Those metacharacters have
        * to be manually unescaped here. */
        builder.Replace(@"\[", "[").Replace(@"\]", "]").Replace(@"\^", "^");

        // put SQL LIKE wildcard literals back
        builder.Replace("[.*]", "[%]").Replace("[.]", "[_]");

        return builder.ToString();
    }
}

string pattern = @".*ine.*e$";

var res = list.Where( e => Regex.IsMatch( e, pattern));

var query = from c in ctx.Customers

            where c.City.StartsWith("Lo")

            select c;

will generate this SQL statement:
SELECT CustomerID, CompanyName, ...
FROM    dbo.Customers
WHERE  City LIKE [Lo%]

var query = from c in ctx.Customers

            where c.City.StartsWith("L") && c.City.Contains("n")

            select c;

generates the statement:
SELECT CustomerID, CompanyName, ...
FROM    dbo.Customers
WHERE  City LIKE [L%]
AND      City LIKE [%n%]

var query = from c in ctx.Customers

            where SqlMethods.Like(c.City, "L_n%")

            select c;

SELECT CustomerID, CompanyName, ...
FROM    dbo.Customers
WHERE  City LIKE [L_n%]

using System;
using System.Text.RegularExpressions;

public static class MyExtensions
{
    public static bool Like(this string s, string pattern, RegexOptions options = RegexOptions.IgnoreCase)
    {
        return Regex.IsMatch(s, pattern, options);
    }
}

string pattern = ".*ine.*e";
var res = from i in list
    where i.Like(pattern)
    select i;

public static IEnumerable<T> Like<T>(this IEnumerable<T> lista, Func<T, string> type, string pattern)
            {

                int[] pf = prefixFunction(pattern);

                foreach (T e in lista)
                {
                    if (patternKMP(pattern, type(e), pf))
                        yield return e;
                }

            }

            private static int[] prefixFunction(string p)
            {


                int[] pf = new int[p.Length];
                int k = pf[0] = -1;


                for (int i = 1; i < p.Length; i++)
                {
                    while (k > -1 && p[k + 1] != p[i])
                        k = pf[k];

                    pf[i] = (p[k + 1] == p[i]) ? ++k : k;
                }
                return pf;

            }

            private static bool patternKMP(string p, string t, int[] pf)
            {

                for (int i = 0, k = -1; i < t.Length; i++)
                {

                    while (k > -1 && p[k + 1] != t[i])
                        k = pf[k];

                    if (p[k + 1] == t[i])
                        k++;

                    if (k == p.Length - 1)
                        return true;    
                }

                return false;

            }