String::IndexOf Method (Char, Int32, Int32)
Reports the zero-based index of the first occurrence of the specified character in this instance. The search starts at a specified character position and examines a specified number of character positions.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
-
Type:
System::Char
A Unicode character to seek.
- startIndex
-
Type:
System::Int32
The search starting position.
- count
-
Type:
System::Int32
The number of character positions to examine.
Return Value
Type: System::Int32The zero-based index position of value from the start of the string if that character is found, or -1 if it is not.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | count or startIndex is negative. -or- startIndex is greater than the length of this string. -or- count is greater than the length of this string minus startIndex. |
The search begins at startIndex and continues to startIndex + count -1. The character at startIndex + count is not included in the search.
Index numbering starts from 0 (zero). The startIndex parameter can range from 0 to the length of the string instance.
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 the IndexOf method.
// Example for the String::IndexOf( Char, int, int ) method. using namespace System; void FindAllChar( Char target, String^ searched ) { Console::Write( "The character '{0}' occurs at position(s): ", target ); int startIndex = -1; int hitCount = 0; // Search for all occurrences of the target. while ( true ) { startIndex = searched->IndexOf( target, startIndex + 1, searched->Length - startIndex - 1 ); // Exit the loop if the target is not found. if ( startIndex < 0 ) break; Console::Write( "{0}, ", startIndex ); hitCount++; } Console::WriteLine( "occurrences: {0}", hitCount ); } int main() { String^ br1 = "0----+----1----+----2----+----3----+----" "4----+----5----+----6----+----7"; String^ br2 = "0123456789012345678901234567890123456789" "0123456789012345678901234567890"; String^ str = "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " "ABCDEFGHI abcdefghi ABCDEFGHI"; Console::WriteLine( "This example of String::IndexOf( Char, int, int )\n" "generates the following output." ); Console::WriteLine( "{0}{1}{0}{2}{0}{3}{0}", Environment::NewLine, br1, br2, str ); FindAllChar( 'A', str ); FindAllChar( 'a', str ); FindAllChar( 'I', str ); FindAllChar( 'i', str ); FindAllChar( '@', str ); FindAllChar( ' ', str ); } /* This example of String::IndexOf( Char, int, int ) generates the following output. 0----+----1----+----2----+----3----+----4----+----5----+----6----+----7 01234567890123456789012345678901234567890123456789012345678901234567890 ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI The character 'A' occurs at position(s): 0, 20, 40, 60, occurrences: 4 The character 'a' occurs at position(s): 10, 30, 50, occurrences: 3 The character 'I' occurs at position(s): 8, 28, 48, 68, occurrences: 4 The character 'i' occurs at position(s): 18, 38, 58, occurrences: 3 The character '@' occurs at position(s): occurrences: 0 The character ' ' occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6 */
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