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How to generate random numbers in VB.NET?

Anurag Sharma834120-Oct-2010

Hello Guys,

I am very new in VB.NET and I have a small task to generate random numbers in VB.NET.

Please provide me sample of code.

Thanks 

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Updated on 10-Aug-2011
Anurag Sharma

Anurag Sharma

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2 Answers

manigovi manigovinth

manigovi manigovinth

10-Aug-2011
Hi...i provides sample vb.net codes here...

The following code returns a random number:

Dim num As Integer = random.Next()

The following code returns a random number less than 1000. 

Dim num As Integer = random.Next(1000)

The following code returns a random number between min and max: 

Private Function RandomNumber(min As Integer, max As Integer) As Integer 
   Dim random As New Random() 
   Return random.Next(min, max) 
End Function 'RandomNumber

At some point, you may also want to generate random strings. I have created a method, which takes first parameter as the size of string and second parameter if you want the string to be lowercase.

'/ '/ Generates a random string with the given length 
'/ '/ Size of the string '/ If true, generate lowercase string 
'/ Random string 
Private Function RandomString(size As Integer, lowerCase As Boolean) As String 
   Dim builder As New StringBuilder() 
   Dim random As New Random() 
   Dim ch As Char 
   Dim i As Integer 
   For i = 0 To size - 1 
      ch = Convert.ToChar(Convert.ToInt32((26 * random.NextDouble() + 65))) 
      builder.Append(ch) 
   Next 
   iIf lowerCase Then 
      Return builder.ToString().ToLower() 
   End If 
   Return builder.ToString() 
End Function 'RandomString

You can even combine the two methods-RandomNumber and RandomString to generate a combination of random string and numbers. For example, the following code generates a password of length 10 with first 4 letters lowercase, next 4 letters numbers, and last 2 letters as uppercase. 

Public Function GetPassword() As String 
   Dim builder As New StringBuilder() 
   builder.Append(RandomString(4,True)) 
   builder.Append(RandomInt(1000, 9999)) 
   builder.Append(RandomString(2,False)) 
   Return builder.ToString() 
End Function 'GetPassword


--------------------------------------------------------

Cegonsoft

Uttam Misra

Uttam Misra

20-Oct-2010
Check this

http://msdn.microsoft.com/en-us/library/system.random.aspx

Dim n as Integer
dim sm as Integer
 
Redim cntArray(High-Low)
For x as Integer = 0 to Iter
 n =rand.Next(Low,High)
 sm += 1
 cntArray(n-Low) +=1
Next
 
Dim st1 as string
 
For x As Integer = 0 to cntArray.Length - 1
 st1 = (x +Low).ToString 'The number.
 st1 &="  " & cntArray(x).ToString'The count of that number.
 st1 &="  " & (100 * cntArray(x) /sm).ToString 'The percent of that number
 <your listboxhere>.Items.Add(st1)
Next

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