CDbl Example Syntax VB.NET ASP.NET | CDbl | Source Code

Posted by on Thursday, May 12, 2011 · Leave a Comment 

CDbl Example Syntax VB.NET ASP.NET | CDbl | Source Code

Summary: – Illustrates using with in VB.NET ASP.NET.


View Other VB.NET ASP.NET Source Code Examples


Purpose:
Converts positive and negative numbers into double data type

Syntax:
CDbl(expression)

Parameters Description
expression -1.79769313486231570E+308 through
-4.94065645841246544E-324 for negative values;
4.94065645841246544E-324 through
1.79769313486231570E+308 for positive values.

Result Data Type Description
double double precision floating point number

Quick Example
Dim double1 As Double = CDbl(1.33)
TextBox1.Text = double1 Returns 1.33

Step 1: Click on Visual Basic to Cut-n-paste code into CDbl.aspx.vb

Imports System
Imports System.IO
Imports System.Data
 
'****************************************************************************************
' 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
'
' Quick Example:   Dim double1 As Double = CDbl(1.33)
'       TextBox1.Text = double1 ' Returns 1.33
'
'
'****************************************************************************************
' This example is from http://idealprogrammer.com
' It shows how you can use CDbl syntax in VB.NET ASP.NET
 
 
Partial Class _CDbl
    Inherits System.Web.UI.Page
 
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
 
        Label1.Text = "Example #1: 	CDbl(expression) "
 
        Dim double1 As Double = CDbl(1.33)
 
        TextBox1.Text = double1 ' Returns 1.33
 
        Label2.Text = "Example #2: 	CDbl(expression) "
 
        Dim Double2 As Double = CDbl(-3.4)
 
        TextBox2.Text = Double2 ' Returns -3.4
 
        Label3.Text = "Example #3: 	CDbl(expression)"
 
        Dim Double3 As Double = CDbl(5)
 
        TextBox3.Text = Double3 ' Returns 5
 
 
    End Sub
End Class

Step 2: Click on XML to Cut-n-paste code into CDbl.aspx

< %@ Page Language="VB" AutoEventWireup="false" CodeFile="CDbl.aspx.vb" Inherits="_CDbl" %>
 
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h1><asp:label ID="Label1" runat="server" Text="Label"></asp:label> </h1>
         <asp:textbox ID="TextBox1" runat="server"></asp:textbox><br />
          <h1><asp:label ID="Label2" runat="server" Text="Label"></asp:label> </h1>
         <asp:textbox ID="TextBox2" runat="server"></asp:textbox><br />
          <h1><asp:label ID="Label3" runat="server" Text="Label"></asp:label> </h1>
         <asp:textbox ID="TextBox3" runat="server"></asp:textbox><br />
 
 
 
    </div>
    </form>
</body>
</html>

Prerequistes:

  1. Install Visual Web Developer 2010
  2. Install SQL Server Express
  3. Download Northwind and Pubs Databases
  4. Attach Northwind Database to Databases in Sql Express
  5. Attach pubs Database to Databases in Sql Express

Notes:

  • You can build your own library of syntax examples by using same web site over and over and just add new web forms to it.

Instructions:

VB.NET ASP.NET Syntax Functions CDbl
  1. Use Visual Web Developer 2010
  2. Create new web site;
    • Click File/New Web Site
    • Select ASP.NET Website Template
    • Select Visual Basic for Language
    • name of Web Site could be VBNET_ASPNET_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 Web Form Named CDbl to TypeConversionFunctions folder
    • Right-click TypeConversionFunctions folder;
    • add new item;
    • Select Web Form
    • Check place code behind in separate file
    • Web Form name could be CDbl
  7. Click on Visual Basic in step 1 at the top of this page to copy code into code-behind CDbl.aspx.vb
  8. Click on XML in step 2 above to copy code into web form CDbl.aspx
  9. Right-click on CDbl.aspx in solution explorer and select view in browser

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