VB.NET CDbl Example – Code Sample Syntax

VB.NET CDbl Example – Code Sample Syntax

Purpose: – Illustrates using VB.NET CDbl Code Example.

Description:
Converts positive and negative numbers into double data type

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

Public Class clsCDbl
 
    Public Sub Main()
 
 
        '****************************************************************************************
        ' Purpose: Converts positive and negative numbers into double data type
        '
        ' Syntax: 	CDbl(expression)
        '
        ' Parameter1: expression - -1.79769313486231570E+308 through 
        ' -4.94065645841246544E-324 for negative values; 
        ' 4.94065645841246544E-324 through 
        ' 1.79769313486231570E+308 for positive values.
        '
        ' Result: double - double precision floating point number
        '
        '
        '****************************************************************************************
        ' This example is from http://idealprogrammer.com
 
        Console.WriteLine("Example #1: 	CDbl(expression)")
 
        Dim double1 As Double = CDbl(1.33)
 
        Console.WriteLine(double1) ' Returns 1.33
 
        'write blank line to make output easier to read
        Console.WriteLine()
 
        Console.WriteLine("Example #2: 	CDbl(expression)")
 
        Dim Double2 As Double = CDbl(-3.4)
 
        Console.WriteLine(Double2) ' Returns -3.4
        'write blank line to make output easier to read
        Console.WriteLine()
 
        Console.WriteLine("Example #3: 	CDbl(expression)")
 
        Dim Double3 As Double = CDbl(5)
 
        Console.WriteLine(CDbl(Double3)) ' Returns 5
 
        '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 myclsCDbl As New clsCDbl
        myclsCDbl.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:

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 “Functions”
   • Right-click project name in solution explorer;
   • add new folder;
   • name of folder could be: Functions
4. Add New subfolder named “ConversionFunctions”
   • Right-click Functions folder in solution explorer;
   • add new folder;
   • name of folder could be: ConversionFunctions
5. Add New subfolder named “TypeConversionFunctions”
   • Right-click ConversionFunctions folder in solution explorer;
   • add new folder;
   • name of folder could be: TypeConversionFunctions
6. Add Class Named clsCDbl to TypeConversionFunctions folder
   • Right-click TypeConversionFunctions folder;
   • add new item;
   • Select class
   • Class name could be clsCDbl
7. Click on Visual Basic in code in step 1 above to copy code into clsCDbl.vb
8. Click on Visual Basic in code in step 2 above to copy code into Module1.vb
9. Click green arrow or press F5 to run program