How to: search within a string (Visual Basic)

This article shows an example of how to search within a string in Visual Basic.


This example calls the IndexOf method on a String object to report the index of the first occurrence of a substring:

Dim SearchWithinThis As String = "ABCDEFGHIJKLMNOP"
Dim SearchForThis As String = "DEF"
Dim FirstCharacter As Integer = SearchWithinThis.IndexOf(SearchForThis)

Robust programming

The IndexOf method returns the location of the first character of the first occurrence of the substring. The index is 0-based, which means the first character of a string has an index of 0.

If IndexOf does not find the substring, it returns -1.

The IndexOf method is case-sensitive and uses the current culture.

For optimal error control, you might want to enclose the string search in the Try block of a Try...Catch...Finally Statement construction.

See also