How to: Search Within a String (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)

Compiling the Code

This example requires:

Robust Programming

The IndexOf method reports 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