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String.LastIndexOf Method (String)

Updated: August 2009

Reports the index position of the last occurrence of a specified String within this instance.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public int LastIndexOf(
	string value


Type: System.String

A String to seek.

Return Value

Type: System.Int32
The index position of value if that string is found, or -1 if it is not. If value is Empty, the return value is the last index position in this instance.


value is null.

Index numbering starts from zero. That is, the first character in the string is at index zero and the last is at Length - 1.

The search begins at the last character position of this instance and proceeds backward toward the beginning until either value is found or the first character position has been examined.

This method performs a word (case-sensitive and culture-sensitive) search using the current culture.

The following example removes opening and closing HTML tags from a string if the tags begin and end the string. If a string ends with a closing bracket character (">"), the example uses the LastIndexOf method to locate the start of the end tag.

using System;

public class Example 
   public static void Main() 
      string[] strSource = { "<b>This is bold text</b>", "<H1>This is large Text</H1>",
               "<b><i><font color=green>This has multiple tags</font></i></b>",
               "<b>This has <i>embedded</i> tags.</b>",
               "This line ends with a greater than symbol and should not be modified>" };

      // Strip HTML start and end tags from each string if they are present. 
      foreach (string s in strSource)
         Console.WriteLine("Before: " + s);
         string item = s;
         // Use EndsWith to find a tag at the end of the line. 
         if (item.Trim().EndsWith(">")) 
            // Locate the opening tag. 
            int endTagStartPosition = item.LastIndexOf("</");
            // Remove the identified section, if it is valid. 
            if (endTagStartPosition >= 0 )
               item = item.Substring(0, endTagStartPosition);

            // Use StartsWith to find the opening tag. 
            if (item.Trim().StartsWith("<"))
               // Locate the end of opening tab. 
               int openTagEndPosition = item.IndexOf(">");
               // Remove the identified section, if it is valid. 
               if (openTagEndPosition >= 0)
                  item = item.Substring(openTagEndPosition + 1);
         // Display the trimmed string.
         Console.WriteLine("After: " + item);
// The example displays the following output: 
//    Before: <b>This is bold text</b> 
//    After: This is bold text 
//    Before: <H1>This is large Text</H1> 
//    After: This is large Text 
//    Before: <b><i><font color=green>This has multiple tags</font></i></b> 
//    After: <i><font color=green>This has multiple tags</font></i> 
//    Before: <b>This has <i>embedded</i> tags.</b> 
//    After: This has <i>embedded</i> tags. 
//    Before: This line ends with a greater than symbol and should not be modified> 
//    After: This line ends with a greater than symbol and should not be modified>

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0




August 2009

Replaced the example.

Customer feedback.

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