using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"<item>.*?<id>((?:(?!<id>).)*?)</id>(?:(?!<item>).)*<img>(.*?)</img>.*?</item>";
string input = @"<set>
<item>
<id>1</id>
<title>title1</title>
</item>
<item>
<id>2</id>
<title>title2</title>
</item>
<item>
<id>3</id>
<title>title3</title>
<img>img3</img>
</item>
</set>";
RegexOptions options = RegexOptions.Singleline | RegexOptions.IgnoreCase;
foreach (Match m in Regex.Matches(input, pattern, options))
{
Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
}
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx