| Description |
Returns the index of the Needle string in the current (haystack) string.
If not found, then -1 is returned.
The scan is case sensitive.
The scan starts at the beginning and continues until either the Needle is found, or the string is exhausted.
The scan can be forced to commence from the Start character, and can be limited to Count scan characters.
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| | Notes | Very Important : Methods in .Net treat strings as starting at 0, unlike traditional Delphi where they started at 1.
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| Microsoft MSDN Links |
system
system.String
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| A simple example |
program Project1;
{$APPTYPE CONSOLE}
var
strA : String;
result : Integer;
begin
strA := '123456789';
Console.WriteLine('strA = ' + strA);
result := strA.IndexOf('45');
Console.WriteLine('Index of 45 = ' + result.ToString);
result := strA.IndexOf('54');
Console.WriteLine('Index of 54 = ' + result.ToString);
Console.ReadLine;
end.
| | Show full unit code | strA = 123456789
Index of 45 = 3
Index of 54 = -1
| | | Specifying a start position | program Project1;
{$APPTYPE CONSOLE}
var
strA : String;
result : Integer;
begin
strA := 'ABCABCABC';
result := strA.IndexOf('AB', 5);
Console.WriteLine('strA = ' + strA);
Console.WriteLine('Looking for AB, starting from index 5');
Console.WriteLine('Result = ' + result.ToString);
Console.ReadLine;
end.
| | Show full unit code | strA = ABCABCABC
Looking for AB, starting from index 5
Result = 6
| | | Specifying a start position and limit in the character scan | // Full Unit code.
// -------------------------------------------------------------
// Create a new WinForm application, double click the form to
// create an OnLoad event, and then replace the WinForm unit
// with this text.
unit WinForm;
interface
uses
System.Drawing, System.Collections, System.ComponentModel,
System.Windows.Forms, System.Data;
type
TWinForm = class(System.Windows.Forms.Form)
\{REGION 'Designer Managed Code'\} // Note that REGION and ENREGION should be prefixed by a dollar sign
strict private
///
/// Required designer variable.
///
Components: System.ComponentModel.Container;
///
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///
procedure InitializeComponent;
procedure TWinForm_Load(sender: System.Object; e: System.EventArgs);
{ENDREGION}
strict protected
///
/// Clean up any resources being used.
///
procedure Dispose(Disposing: Boolean); override;
private
{ Private Declarations }
public
constructor Create;
end;
[assembly: RuntimeRequiredAttribute(TypeOf(TWinForm))]
implementation
\{REGION 'Windows Form Designer generated code'\}
///
/// Required method for Designer support -- do not modify
/// the contents of this method with the code editor.
///
procedure TWinForm.InitializeComponent;
begin
//
// TWinForm
//
Self.AutoScaleBaseSize := System.Drawing.Size.Create(5, 13);
Self.ClientSize := System.Drawing.Size.Create(292, 266);
Self.Name := 'TWinForm';
Self.Text := 'WinForm';
Include(Self.Load, Self.TWinForm_Load);
end;
{ENDREGION}
procedure TWinForm.Dispose(Disposing: Boolean);
begin
if Disposing then
begin
if Components <> nil then
Components.Dispose();
end;
inherited Dispose(Disposing);
end;
constructor TWinForm.Create;
begin
inherited Create;
//
// Required for Windows Form Designer support
//
InitializeComponent;
//
// TODO: Add any constructor code after InitializeComponent call
//
end;
procedure TWinForm.TWinForm_Load(sender: System.Object; e: System.EventArgs);
program Project1;
{$APPTYPE CONSOLE}
var
strA : String;
result : Integer;
begin
strA := 'ABCABCABC';
Console.WriteLine('Guide= 0123456789');
Console.WriteLine('strA = ' + strA);
result := strA.IndexOf('ABC', 5, 3);
Console.WriteLine('Looking for ABC, starting @ 5 for count of 3');
Console.WriteLine('Result = ' + result.ToString);
result := strA.IndexOf('ABC', 5, 4);
Console.WriteLine('Looking for ABC, starting @ 5 for count of 4');
Console.WriteLine('Result = ' + result.ToString);
Console.ReadLine;
end.
end. | | Hide full unit code | Guide= 0123456789
strA = ABCABCABC
Looking for ABC, starting @ 5 for count of 3
Result = -1
Looking for ABC, starting @ 5 for count of 4
Result = 6
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