Like(searchString) & ReverseLike(compareString)
Extension method compareString.Like(searchString) to compare a string using SQL Like style wildcards, and searchString.ReverseLike(compareString). Wildcards like "a", "a%", "%b", "a%b" and "a%b%c" supported.
Source
public static class StringLikeExtensions
{
/// <summary>
/// Tests a string to be Like another string containing SQL Like style wildcards
/// </summary>
/// <param name="value">string to be searched</param>
/// <param name="searchString">the search string containing wildcards</param>
/// <returns>value.Like(searchString)</returns>
/// <example>value.Like("a")</example>
/// <example>value.Like("a%")</example>
/// <example>value.Like("%b")</example>
/// <example>value.Like("a%b")</example>
/// <example>value.Like("a%b%c")</example>
/// <remarks>base author -- Ruard van Elburg from StackOverflow, modifications by dvn</remarks>
/// <remarks>converted to a String extension by sja</remarks>
/// <seealso cref="https://stackoverflow.com/questions/1040380/wildcard-search-for-linq"/>
public static bool Like(this String value, string searchString)
{
bool result = false;
var likeParts = searchString.Split(new char[] { '%' });
for (int i = 0; i < likeParts.Length; i++)
{
if (likeParts[i] == String.Empty)
{
continue; // "a%"
}
if (i == 0)
{
if (likeParts.Length == 1) // "a"
{
result = value.Equals(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
else // "a%" or "a%b"
{
result = value.StartsWith(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
}
else if (i == likeParts.Length - 1) // "a%b" or "%b"
{
result &= value.EndsWith(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
else // "a%b%c"
{
int current = value.IndexOf(likeParts[i], StringComparison.OrdinalIgnoreCase);
int previous = value.IndexOf(likeParts[i - 1], StringComparison.OrdinalIgnoreCase);
result &= previous < current;
}
}
return result;
}
/// <summary>
/// Tests a string containing SQL Like style wildcards to be ReverseLike another string
/// </summary>
/// <param name="value">search string containing wildcards</param>
/// <param name="compareString">string to be compared</param>
/// <returns>value.ReverseLike(compareString)</returns>
/// <example>value.ReverseLike("a")</example>
/// <example>value.ReverseLike("abc")</example>
/// <example>value.ReverseLike("ab")</example>
/// <example>value.ReverseLike("axb")</example>
/// <example>value.ReverseLike("axbyc")</example>
/// <remarks>reversed logic of Like String extension</remarks>
public static bool ReverseLike(this String value, string compareString)
{
bool result = false;
var likeParts = value.Split(new char[] {'%'});
for (int i = 0; i < likeParts.Length; i++)
{
if (likeParts[i] == String.Empty)
{
continue; // "a%"
}
if (i == 0)
{
if (likeParts.Length == 1) // "a"
{
result = compareString.Equals(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
else // "a%" or "a%b"
{
result = compareString.StartsWith(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
}
else if (i == likeParts.Length - 1) // "a%b" or "%b"
{
result &= compareString.EndsWith(likeParts[i], StringComparison.OrdinalIgnoreCase);
}
else // "a%b%c"
{
int current = compareString.IndexOf(likeParts[i], StringComparison.OrdinalIgnoreCase);
int previous = compareString.IndexOf(likeParts[i - 1], StringComparison.OrdinalIgnoreCase);
result &= previous < current;
}
}
return result;
}
}
Example
using System;
using System.Linq;
using System.Collections.Generic;
public class Program
{
public static void Main()
{
List<string> testStrings = new List<string>();
testStrings.Add("DIOM2816X14M");
testStrings.Add("SJ2-35954A-SMT-TR");
testStrings.Add("SOIC127P700X230-16M");
testStrings.Add("SQFP50P1200X1200X170-64M");
var query1 = from test in testStrings
where test.Like("DIOM%")
select test;
Console.WriteLine(query1.FirstOrDefault());
var query2 = from test in testStrings
where test.Like("SJ2%TR")
select test;
Console.WriteLine(query2.FirstOrDefault());
var query3 = from test in testStrings
where test.Like("SOIC127%16%")
select test;
Console.WriteLine(query3.FirstOrDefault());
var query4 = from test in testStrings
where test.Like("SQFP50P%64%")
select test;
Console.WriteLine(query4.FirstOrDefault());
}
}
DIOM2816X14M
SJ2-35954A-SMT-TR
SOIC127P700X230-16M
SQFP50P1200X1200X170-64M