Programming Tutorials

String equals, Copy to & Copy to in VB.net

By: Issac  

String Equals function is handy to check whether two specified string object values are same or not

System.String.Equals(String rudran, String rudran) As Boolean 
Parameters: 
String arguments
1. String rudran
2. String rudran

Returns: 
Boolean : Yes/No
It return the values of the two String Objects are same

For ex :
String1 = "Adhi"
String2 = "Adhi"
String.Equals(String1,String2) returns True
String.Equals(String1.ToLower,String2) returns False
Because the String Objects values are different

Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim string1 As String = "Adhirudran"
Dim string2 As String = "Adhirudran"

If String.Equals(string1, string2) Then
MsgBox("Strings are Equal() ")
Else
MsgBox("Strings are not Equal() ")
End If
End Sub
End Class
When you run this program you will get message "Strings are Equal () " 

To copy a specified number of characters from a specified position in a instance to a specific position in an array of characters
System.String.CopyTo(ByVal sourceIndex As Integer, ByVal destination() As Char, ByVal destinationIndex As Integer, ByVal count As Integer) 

Parameters: 
Integer sourceIndex: The starting position of the source String
Char destination () : The character Array
Integer destinationIndex: Array element in the destination
Integer count: The number of characters to destination

Exceptions: 
System.ArgumentNullException: If the destination is null
System.ArgumentOutOfRangeException: 
Source Index, DestinationIndex or Count is a -ve value
Count is greater than the length of the substring from startIndex to the end of this instance
Count is greater than the length of the subarray from destinationIndex to the end of destination

Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim string1 As String = "CopyTo() sample"
Dim chrs(7) As Char
str1.CopyTo(0, chrs, 0, 6)
MsgBox(chrs(0) + chrs(1) + chrs(2) + chrs(3) + chrs(4) + chrs(5)+ chrs(6)+chr(7))
End Sub
End Class
When you run this Source code you will get CopyTo() in MessageBox

To create a new string object with the same conent we use String copy method.
System.String.Copy(ByVal str As String) As String 

Parameters: 
String str: The argument String for Copy method

Returns: 
String: Returns a new String as the same content of argument String

Exceptions:
System.ArgumentNullException : If the argument is null.

Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim string1 As String
Dim string2 As String

string1 = "m-indya.com"
string2 = String.Copy(string1)

MsgBox(string2)
End Sub
End Class

When you run this source code you will get same content of str1 in str2 (ie m-indya.com)

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