[VB.NET][TUT] STRINGS - Big TUT Collection Part 2

-------How to VB.NET String.IndexOf()

The IndexOf method in String Class returns the index of the first occurrence of the specified substring.

System.String.IndexOf(String str) As Integer

Parameters:

str - The parameter string to check its occurrences

Returns:

Integer - If the parameter String occurred as a substring in the specified String

it returns position of the first character of the substring .

If it does not occur as a substring, -1 is returned.

Exceptions:

System.ArgumentNullException: If the Argument is null.

For ex:

"This is a test".IndexOf("Test") returns 10


"This is a test".IndexOf("vb") returns -1

Example:

 Public Class Form1  
   Private Sub Button1_Click(ByVal sender As System.Object, _  
   ByVal e As System.EventArgs) Handles Button1.Click  
     Dim str As String  
     str = "VB.NET TOP 10 BOOKS"  
     MsgBox(str.IndexOf("BOOKS"))  
   End Sub  
 End Class  

-------How to VB.NET String.Format()

VB.NET String Format method replace the argument Object into a text equivalent System.Striing.

System.Format(ByVal format As String, ByVal arg0 As Object) As String

Parameters:

String format : The format String

The format String Syntax is like {indexNumber:formatCharacter}

Object arg0 : The object to be formatted.

Returns:

String : The formatted String

Exceptions:

System.ArgumentNullException : The format String is null.

System.FormatException : The format item in format is invalid.

The number indicating an argument to format is less than zero, or greater than or equal to the number of specified objects to format.

For ex :

Currency :

String.Format("{0:c}", 10) will return $10.00

The currency symbol ($) displayed depends on the global locale settings.

Date :

String.Format("Today's date is {0:D}", DateTime.Now)

You will get Today's date like : 01 January 2005

Time :

String.Format("The current time is {0:T}", DateTime.Now)

You will get Current Time Like : 10:10:12

Example:

 Public Class Form1  
   Private Sub Button1_Click(ByVal sender As System.Object, _  
   ByVal e As System.EventArgs) Handles Button1.Click  
     Dim dNum As Double  
     dNum = 32.123456789  
     MsgBox("Formated String " & String.Format("{0:n4}", dNum))  
   End Sub  
 End Class