VB.NET IndexOf() – Code Sample

VB.NET IndexOf Example – Code Sample Syntax

Abstract: – Illustrates using .

 *** 1. Download Source Code *** 

VB.NET Syntax StringManipulation IndexOf download Download Source Code for All VB Console Examples in One Project

 *** 2. IndexOf Syntax *** 


Purpose:
Returns an integer that represents the position of the first occurrence of the
specified number of characters. If you specify startIndex, that specifies
where to start looking. If you specify count, that specifies how many characters to
to search past start. If the string is not found, this method returns -1


Syntax:
string.IndexOf(matchstring[, startIndex][,count])

Parameters Description
string Required – string to be searched
matchstring Required – string that you are looking
for in parameter1
startIndex Optional. specifies where to start looking. Zero-based.
count Optional. specifies how many characters to
to search past start.

Result Data Type Description
integer Returns an integer that represents the position of the first
occurrence of the specified number of characters. If the string is not found,
this method returns -1. The integer returned is a zero-based index so the first
position is represented by 0 instead of 1.


 *** 3. IndexOf – Quick Example *** 

Dim strIndexOfExample As String = “This is a test string”
Console.WriteLine(strIndexOfExample.IndexOf(“is”)) ‘Returns 2
Console.WriteLine(strIndexOfExample.IndexOf(“xyz”)) ‘Returns -1 (not found)

 *** 4. IndexOf – Full Example *** 

IndexOf Example Output Screenshot


VB.NET Syntax StringManipulation IndexOf screenshot


Step 1: Click Visual Basic to Cut-n-paste code into clsIndexOf.vb

Public Class clsIndexOf
 
    Public Sub Main()
 
 
        '****************************************************************************************
        ' Purpose:  Returns an integer that represents the position of the first occurrence of the
        ' specified number of characters. If you specify startIndex, that specifies
        ' where to start looking. If you specify count, that specifies how many characters to 
        ' to search past start. If the string is not found, this method returns -1
        '
        ' Syntax: 	string.IndexOf(matchstring[, startIndex][,count])
        '
        ' Parameter1: string - Required - string to be searched
        '
        ' Parameter2: matchstring - Required - string that you are looking 
        ' for in parameter1
        '
        ' Parameter3: startIndex - Optional. specifies where to start looking. Zero-based.
        '
        ' Parameter4: count - Optional. specifies how many characters to 
        ' to search past start.
        '
        ' Result: integer - Returns an integer that represents the position of the first 
        ' occurrence of the specified number of characters. If the string is not found, 
        ' this method returns -1.  The integer returned is a zero-based index so the first
        ' position is represented by 0 instead of 1.
        '
        ' Quick Example:    Dim strIndexOfExample As String = "This is a test string"
        ' Console.WriteLine(strIndexOfExample.IndexOf("is")) 'Returns 2
        ' Console.WriteLine(strIndexOfExample.IndexOf("xyz")) 'Returns -1 (not found)
        '
        ' 
        '****************************************************************************************
 
 
        Console.WriteLine("Example #1: string.IndexOf(matchstring[, startIndex][,count]) ")
 
        Dim strIndexOfExample As String = "This is a test string"
 
        Console.WriteLine(strIndexOfExample.IndexOf("is")) 'Returns 2
 
        Console.WriteLine(strIndexOfExample.IndexOf("xyz")) 'Returns -1 (not found)
 
        Console.WriteLine(strIndexOfExample.IndexOf("T"), 0) 'Returns 0 
 
        'write blank line to make output easier to read
        Console.WriteLine()
 
        'Prevent console from closing before you press enter
        Console.ReadLine()
 
    End Sub
 
 
End Class

Step 2: Click Visual Basic to Cut-n-paste code into Module1.vb

Module Module1
 
    Sub Main()
 
 
        Dim myclsIndexOf As New clsIndexOf
        myclsIndexOf.Main()
 
 
 
    End Sub
 
End Module

Prerequistes:

  1. Install Visual Basic (Express or Standard Edition)
  2. Install SQL Server Express
  3. Download Northwind and pubs Database
  4. Attach Northwind Database to Databases in Sql Express
  5. Attach pubs Database to Databases in Sql Express

Notes:

  • Console Application is used to simplify things, but Windows Forms or Web Forms could also be used
  • You can build a library of syntax examples by using same project over and over and just commenting out what you do not want to execute in Module1.vb

Instructions:
VB.NET Syntax StringManipulation IndexOf

  1. Use Visual Basic 2010 Express or Standard Edition
  2. Create new project;
    • Click File/New Project
    • Select Console Application Template
    • Select Visual Basic for Language
    • name of project could be VBNET_Syntax.
  3. Add New folder named “StringManipulation”
    • Right-click project name in solution explorer;
    • add new folder;
    • name of folder could be: StringManipulation
  4. Add Class Named clsIndexOf to StringManipulation folder
    • Right-click StringManipulation folder;
    • add new item;
    • Select class
    • Class name could be clsIndexOf
  5. Click on Visual Basic in code in step 1 above to copy code into clsIndexOf.vb
  6. Click on Visual Basic in code in step 2 above to copy code into Module1.vb
  7. Click green arrow or press F5 to run program