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String.IndexOfAny Method (Char[], Int32)

Reports the zero-based index of the first occurrence in this instance of any character in a specified array of Unicode characters. The search starts at a specified character position.

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

public int IndexOfAny(
	char[] anyOf,
	int startIndex


Type: System.Char[]
A Unicode character array containing one or more characters to seek.
Type: System.Int32
The search starting position.

Return Value

Type: System.Int32
The zero-based index position of the first occurrence in this instance where any character in anyOf was found; otherwise, -1 if no character in anyOf was found.


anyOf is null.


startIndex is negative.


startIndex is greater than the number of characters in this instance.

Index numbering starts from zero. startIndex can range from 0 to one less than the length of the string instance.

The search for anyOf is case-sensitive.

This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar value 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.

Platform Notes

Silverlight for Windows Phone Silverlight for Windows Phone

 If you pass an invalid parameter value, IndexOfAny throws an ArgumentOutOfRangeException instead of an ArgumentNullException.

The following code example finds the index of the occurrence of any character of the string "is" within a substring of another string.

// Sample for String.IndexOfAny(Char[], Int32)
using System;

class Example
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
      string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-";
      string br2 = "0123456789012345678901234567890123456789012345678901234567890123456";
      string str = "Now is the time for all good men to come to the aid of their party.";
      int start;
      int at;
      string target = "is";
      char[] anyOf = target.ToCharArray();

      start = str.Length / 2;
      outputBlock.Text += "\n";
      outputBlock.Text += String.Format("The first character occurrence from position {0} to {1}.",
                             start, str.Length - 1) + "\n";
      outputBlock.Text += String.Format("{1}{0}{2}{0}{3}{0}", "\n", br1, br2, str) + "\n";
      outputBlock.Text += String.Format("A character in '{0}' occurs at position: ", target);

      at = str.IndexOfAny(anyOf, start);
      if (at > -1)
         outputBlock.Text += at;
         outputBlock.Text += "(not found)";
      outputBlock.Text += "\n";

The first character occurrence from position 33 to 66.
Now is the time for all good men to come to the aid of their party.

A character in 'is' occurs at position: 49



Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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