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.

Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison. In a culture-sensitive search, if value contains an ignorable character, the result is equivalent to searching with that character removed. If value consists only of one or more ignorable characters, the LastIndexOf(String) method always returns String.Length – 1, which represents the last index position in the current instance. In the following example, the LastIndexOf(String) method is used to find three substrings (a soft hyphen (U+00AD), a soft hyphen followed by "n", and a soft hyphen followed by "m") in two strings. Only one of the strings contains a soft hyphen. If the example is run on the .NET Framework 4 or later, in each case, because the soft hyphen is an ignorable character, the result is the same as if the soft hyphen had not been included in value. When searching for a soft hyphen only, the method returns 6 and 5. These values correspond to the index of the last character in the two strings.

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.

Module Example
PublicSub Main()
Dim strSource AsString() = { "<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 s AsStringIn strSource
Console.WriteLine("Before: " + s)
' Use EndsWith to find a tag at the end of the line.If s.Trim().EndsWith(">") Then' Locate the opening tag.Dim endTagStartPosition AsInteger = s.LastIndexOf("</")
' Remove the identified section if it is valid.If endTagStartPosition >= 0 Then
s = s.Substring(0, endTagStartPosition)
EndIf' Use StartsWith to find the opening tag.If s.Trim().StartsWith("<") Then' Locate the end of opening tab.Dim openTagEndPosition AsInteger = s.IndexOf(">")
' Remove the identified section if it is valid.If openTagEndPosition >= 0 Then
s = s.Substring(openTagEndPosition + 1)
EndIfEndIfEndIf' Display the trimmed string.
Console.WriteLine("After: " + s)
Console.WriteLine()
NextEndSubEndModule' 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>