String.IndexOf Method (Char)
Reports the zero-based index of the first occurrence of the specified Unicode character in this string.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.Char
A Unicode character to seek.
Return Value
Type: System.Int32The 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.
// Create a Unicode String with 5 Greek Alpha characters String szGreekAlpha = new String('\u0391',5); // Create a Unicode String with a Greek Omega character String szGreekOmega = new String(new char [] {'\u03A9','\u03A9','\u03A9'},2,1); String szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, szGreekOmega.Clone()); // Examine the result Console.WriteLine(szGreekLetters); // The first index of Alpha int ialpha = szGreekLetters.IndexOf('\u0391'); // The last index of Omega int iomega = szGreekLetters.LastIndexOf('\u03A9'); Console.WriteLine("The Greek letter Alpha first appears at index " + ialpha + " and Omega last appears at index " + iomega + " in this String.");
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
