Working with files and
directories is one of my favorites! With the help of the namespace, System.IO we can parse through the entire hard disk of our
computer. The System.IO namespace has rich inbuilt
methods/functions for every common task that we need to do. With the help of
these functions, we can easily write code for:
Does this file exist?
What is the size of this file?
Delete this file
Get all files in this directory ... and so on.
But the said namespace or other namespace does not provide us with a function
which gives the directory size. One way to find the directory size of any
folder/directory is as follows:
1) Start from the directory/folder that we need to find the size
2) Find all files in the current directory
3) Loop through each file and find the size of
each file
4) Chances are, we may end up with sub-folders.
5) We also need to find the number of files in this sub-folder
6) Since this is a repeating process, we should have a recursive mechanism were
we will parse through the end (until no more sub-directories exists)
The following example consists of three functions. A) Public DirectorySize(ByValstrStartDirectory as String)
B) Private FindDirectorySize(ByVal strCurrentDir As String)
C) Private Sub RecursiveParseDirectory(ByValstrDirectory As String)
Include all the three functions in aspx or codebehind page and invoke the function, DirectorySize. Pass the folder/directory name as an
argument to this method and it will return you the size of the directory. You
will also need to declare a global variable called: intDirectorySize which is of type, Integer.
Dim intDirectorySize As Integer
Public Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
' For this example, I have used "." which represents the current
directory
lblMsg.Text =
"Directory size is " & DirectorySize(".")
End Sub
Public Function DirectorySize(ByVal strStartDir As String)
Dim strStartDirectory As String = Server.MapPath(strStartDir)
FindDirectorySize(strStartDirectory)
RecursiveParseDirectory(strStartDirectory)
Return intDirectorySize
End Function
Private Sub RecursiveParseDirectory(ByValstrDirectory As String)
Dim strTemp As String
Dim arrSubDirectories()
As String = Directory.GetDirectories(strDirectory)
For Each strTemp In arrSubDirectories
FindDirectorySize(strTemp)
RecursiveParseDirectory(strTemp)
Next
End Sub
Private Sub FindDirectorySize(ByVal strCurrentDir As String)
Dim DI As DirectoryInfo = New DirectoryInfo(strCurrentDir)
We have already known how to upload the file in the server, in this<br />program we will see How to retrieve the properties of file uploaded by the user
We have already known how to
upload the file in the server, in this program we will see How to retrieve the
properties of file uploaded by the user.
We can retrieve some of
the interesting and useful properties of the file that is uploaded to the
webserver. The PostedFile provides us with three important properties, such as
FileName, ContentType and ContentLength. In our previous example, we already
saw, how to use the property, FileName? Now, we will see, how to know the size
of the file uploaded, and how to know the contentType of the file uploaded.
The following line of code
retrieves the ContentType of the file uploaded.
How to control the size of file
uploaded to the web server?
While uploading a file to
the web server, we have a limit of 4MB by default. We can either decrease or
increase this value. The value is set in the key, maxRequestLength of machine
config file.
There is a maxRequestLength limit in the machine.config file (look for the
<system.web> section); in the http Runtime settings that you need to
alter/raise if you want to accept anything larger than 4Mb. These are the
standard settings for the httpRuntime:
Sending email is a very common task in any web application
Sending email is a very common task in any
web application. In almost every web application (web site), their will at
least be an occasion to send email in any fashion. In classic ASP, we worked
with the CDONTS object to send emails from an ASP page. The SMTP Mail class in
ASP .NET provides properties and methods for sending messages using the
Collaboration Data Objects for Windows 2000 (CDOSYS) message component In this
article, we will see, how can we send email from an ASP .NET page. In a nut
shell, today, we will be looking into the following:
What we need to send Email
from an ASP .NET?
How to send an email from
an ASP .NET page?
What is new in sending
email? (SmtpMail.SmtpServer)
What we need to send Email
from an ASP .NET?
The first thing that you need is the SMTP
service. SMTP service should be up and running. And you also need to import the
namespace, System.Web.Mail. To create a mail object, you need to create
an instance of MailMessage. MailMessage has all required properties such
as To, Subject, BCC, CC etc. For a complete list of method and properties, that
you can make use of, please visit
How to send an email from an
ASP .NET page?
<%@ Import Namespace="System.Web.Mail" %>
<html>
<script language="VB" runat="server">
Sub Page_Load(Sender As Object, E As EventArgs)
Dim msg as New MailMessage()
msg.To = "saurav@vb-tek.com"
msg.From = "abhi@vb-tek.com"
msg.Subject = "test"
'msg.BodyFormat = MailFormat.Html
msg.BodyFormat = MailFormat.Text
msg.Body = "hi"
SmtpMail.SmtpServer = "localhost"
SmtpMail.Send(msg)
msg = Nothing
lblMsg.Text = "An Email has been send to
" & "das@silicomm.com"
End Sub
</script>
<body style="font: 10pt verdana">
<form runat=server>
<asp:Label id=lblMsg runat=Server /> </form>
</body>
</html>
In the above example, we
start the coding by importing the namespace, "System.Web.Mail". Then,
in the Page_Load event, we create an instance of MailMessage object. It is
through the MailMessage object, we set all the properties such as To, From,
Subject, Body etc. We can either send a text message or a html message. We need
to specify the bodyformat in the BodyFormat property. One we set all the
properties, it is ready to send the email. Before sending the email, you have
to set another important property, ie; SmtpServer. You have to set this
property. You should assign the name of your SMTP server to this property. In
most cases you can assign this as "localhost". If you do not set this
property, then you will not be able to send email from an ASP .NET page.
Finally we send the email using SmtpMail.Send. This method expects the
MailMessage as an argument. Actually the method Send is overloaded. You can
also send an email by specifiying, SmtpMail.Send (From, To, subject, body).
Asking the user to upload a file to the server is a very very common task in most of the web applications. In classic ASP, uploading file was a very difficult task, since we need a third party component or we need to write our component to upload file from client to the server. In ASP .NET Uploading a file from client to the web server is so easy. To be precise, we can get this done in two lines of code. Yes, two lines of code. In this article, we will be looking into the following:
How to Upload a file from
Client to the Web server in ASP .NET?
First of all, we need a HTML server control to allow the user to select the file. This is nothing but the same old <input tag, with the type set to File, such as <input
type=file id=myFilerunat=server
/>. This will give you the textbox and a browse button. Once you have this, the user can select any file from their computer (or even from a network). Then, in the Server side, we need the following line to save the file to the Web Server.
In the above example, you
should note that, in the FORM tag, we have set the ectype to "multipart/form-data".
This is another important aspect while uploading a file to the web server. We
have aInput
tag which is of type file. Then we have a button called
"Upload". On the onclick of the button, you
can see that, we are using some string functions to find the FileName (excluding the path). Finally, we invoke the
method SaveAs to save the file (upload) in the web server.
In this program we will show you how to work with registry.
this program is going to hide the turnoff option from the start menu
Just Copy and paste this simple code into your vb.net application and log off your computer and next log on having the same user account then will not be able to shutdown your computer.
In code window above the class Form1 write following line to import
Imports Mycrosoft.Win32
Then take a button and write down the following code into Button1_Click Subroutine
PrivateSub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
In this program a browser will be created and we will be able to be
Back, forward, refresh, stop, and go to homepage. The form will
Look as follow.
In code window above the class Form1 write following 4 lines to import
Imports System.IO
Imports System.Net
Imports System.Text
Imports System.Windows.Forms
Now double click the back button and write the following code in side button1_Click sub.
PrivateSub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
WebBrowser1.GoBack()
TextBox1.Text = WebBrowser1.Url.ToString()
EndSub
Now double click the Forward button and write the following code in side button2_Click sub
PrivateSub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
WebBrowser1.GoForward()
TextBox1.Text = WebBrowser1.Url.ToString()
EndSub
Now double click the Stop button and write the following code in side button3_Click sub
PrivateSub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
WebBrowser1.Stop()
EndSub
Now double click the Refresh button and write the following code in side button4_Click sub
PrivateSub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
WebBrowser1.Refresh()
EndSub
Now double click the home button and write the following code in side button5_Click sub
PrivateSub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
WebBrowser1.GoHome()
TextBox1.Text = WebBrowser1.Url.ToString()
EndSub
Now double click the form and write the following code in side from load Click sub
PrivateSub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesMyBase.Load
Button1.Enabled = False
Button2.Enabled = False
Button3.Enabled = False
EndSub
Now double click the web browser1 and choose from the Dropdown event to
“CanGoBackChanged”.
Now write the following code in sub
WebBrowser1_CanGoBackChanged
PrivateSub WebBrowser1_CanGoBackChanged(ByVal sender AsObject, ByVal e As System.EventArgs) Handles WebBrowser1.CanGoBackChanged
If WebBrowser1.CanGoBack = TrueThen
Button1.Enabled = True
Else
Button1.Enabled = False
EndIf
EndSub
Now do the same and create Sub WebBrowser1_CanGoForwardChanged
And write the following code inside the sub.
PrivateSub WebBrowser1_CanGoForwardChanged(ByVal sender AsObject, ByVal e As System.EventArgs) Handles WebBrowser1.CanGoForwardChanged
If WebBrowser1.CanGoForward = TrueThen
Button2.Enabled = True
Else
Button2.Enabled = False
EndIf
EndSub
Again do the same for the following sub WebBrowser1_DocumentCompleted
PrivateSub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
Button3.Enabled = False
EndSub
Again do the same for the following WebBrowser1_Navigated
PrivateSub WebBrowser1_Navigated(ByVal sender AsObject, ByVal e As System.Windows.Forms.WebBrowserNavigatedEventArgs) Handles WebBrowser1.Navigated
TextBox1.Text = WebBrowser1.Url.ToString()
Me.Text = WebBrowser1.DocumentTitle.ToString()
EndSub
Again do the same for the following WebBrowser1_Navigating
PrivateSub WebBrowser1_Navigating(ByVal sender AsObject, ByVal e As System.Windows.Forms.WebBrowserNavigatingEventArgs) Handles WebBrowser1.Navigating
Button3.Enabled = True
EndSub
EndClass
Finally double click the go button and write the following code in side button6_Click sub
PrivateSub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
Microsoft Visual Studio 2010 and the .NET Framework 4 are the next generation of Microsoft development tools. Visual Studio 2010 Professional has been engineered to support the development of applications for Windows, the Web, and Office.
Microsoft Visual Studio 2010 delivers a modern, enhanced user experience that makes understanding the current context more natural.
Clear UI Organization
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Parallel Programming
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IDE support for parallel programming
Native C++ libraries that use lambda functions and align well with STL
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Democratizing Application Lifecycle Management
Visual Studio Team System 2010 delivers new capabilities for everyone on a project, including architects, developers, project managers and testers.
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Visual Studio has made application development more productive, efficient and flexible for both developers and companies. Visual Studio 2010 continues this legacy.
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Build new Windows® 7 applications or upgrade existing applications
Enable Office tools to make your solutions more flexible and productive for specific needs
Web Development
With Visual Studio 2010, we're continuing our investment in great Web development tools.
A high-performance and standards-compliant JavaScript IntelliSense® engine
"One Click Deployment" that quickly publishes files and configuration settings from development machines to the final deployed site
Full support for Silverlight™ for cutting-edge, rich Internet applications
Cloud Development
With Windows Azure™ Tools for Visual Studio, it's easy for developers to build, debug and deploy services and applications for Microsoft's new cloud platform.
C# and VB Project Templates for building Cloud Services
Tools to change the Service Role configuration
Integrated local development via Development Fabric and Development Storage services
Debugging Cloud Service Roles running in the Development Fabric
Building and packaging of Cloud Service Packages
Browsing to the Azure Services Developer Portal
More Databases
With the Visual Studio partner ecosystem, developers will now be able to work with IBM DB2 and Oracle databases in addition to Microsoft SQL Server™ databases.
IBM has committed to develop, sell and support a Database Schema Provider (DSP) to let developers working with DB2 on the Windows, Linux or Unix platforms do offline design, development, testing and change management using Visual Studio Team System 2010 Development Edition.
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Publisher: Coriolis Group Books; 1st edition (April 19, 2002)
Language: English
ISBN-10: 1576108635
ISBN-13: 978-1576108635
Product Description Visual Basic .NET Core Language Little Black Book is an indispensable quick reference guide to Visual Basic .NET syntax and data organization. Readers get a guided tour with an expert programmer who concisely explains how to use the Visual Basic tools, from the Integrated Development Environment to the debugger. It helps readers master common programming tasks, such as working with databases, ASP.NET, ADO.NET, and the core Visual Basic controls. This at-your-fingertips guide focuses on core programming topics and writing code. Plus, it includes a tear-out, quick-reference card summarizing the Visual Basic .NET language.
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In this program at first a simple graphics object will be created and then it will be saved as gif image. First open a project as windows application, and then add a button. Form will look as follow
In code window above the class Form1 write following 2 lines to import
This program will show all the running process in a listbox. Open project as windows application and add one listbox and one button there. Form will look like this
Now double click the button and just copy paste or write the following code inside button1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim plist() As Process Dim myprocess As System.Diagnostics.Process plist = Process.GetProcesses ListBox1.Items.Clear()
For Each myprocess In plist ListBox1.Items.Add(myprocess.ProcessName) Next End Sub
