Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All

String.IndexOf Method (Char)

Reports the zero-based index of the first occurrence of the specified Unicode character in this string.

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

Public Function IndexOf ( _
	value As Char _
) As Integer


Type: System.Char

A Unicode character to seek.

Return Value

Type: System.Int32
The zero-based index position of value if that character is found, or -1 if it is not.

Index numbering starts from zero.

This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar values are the same. To perform a culture-sensitive search, use the CompareInfo.IndexOf method, where a Unicode scalar value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture.

The following example demonstrates how you can search a String for a character using the IndexOf method.

Public Module Example
   Public Sub Main()
      ' Create a Unicode string with 5 Greek Alpha characters. 
      Dim szGreekAlpha As New String(ChrW(&H0391), 5)

      ' Create a Unicode string with 3 Greek Omega characters. 
      Dim szGreekOmega As String = ChrW(&H03A9) + ChrW(&H03A9)+

      Dim szGreekLetters As String = String.Concat(szGreekOmega, szGreekAlpha, _

      ' Display the entire string.

      ' The first index of Alpha. 
      Dim iAlpha As Integer = szGreekLetters.IndexOf(ChrW(&H0391))
      ' The first index of Omega. 
      Dim iomega As Integer = szGreekLetters.IndexOf(ChrW(&H03A9))

      Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
      Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
   End Sub 
End Module 
' The example displays the following output: 
'       The string: OOO?????OOO 
'       First occurrence of the Greek letter Alpha: Index 3 
'       First occurrence of the Greek letter Omega: Index 0

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
© 2015 Microsoft