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.
using System; class Example { static void Main() { // Create a Unicode string with 5 Greek Alpha characters. String szGreekAlpha = new String('\u0391',5); // Create a Unicode string with 3 Greek Omega characters. String szGreekOmega = "\u03A9\u03A9\u03A9"; String szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, szGreekOmega.Clone()); // Display the entire string. Console.WriteLine("The string: {0}", szGreekLetters); // The first index of Alpha. int ialpha = szGreekLetters.IndexOf('\u0391'); // The first index of Omega. int iomega = szGreekLetters.IndexOf('\u03A9'); Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", ialpha); Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", iomega); } } // 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
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1