If any of the steps mentioned in this page is not clear enough,
please post your comments using the feedback form in the bottom of this page. We will add more
explanation here so that it will be helpfull for everybody.
Introduction
SpiderAlerts tool is used by hundreds of our members to receive instant alerts
from dotnetspider about Articles, Jobs, News, Questions and Answers when posted
in the site.
The source code version of SpiderAlerts, which you an download from the link in
the top of this page communicates with a sample web service that you can setup
in your own computer. If you have internet connection, you can change the
SpiderAlerts source code to communicate with the real dotnetspider web
services. This is explained later in this page.
About SpiderAlerts
SpiderAlerts is a windows application that communicates with the web services
hosted by dotnetspider.com. When you minimize, this tool disappears from the
screen and you can see a small icon in the system tray which can be used to re
activate the tool.
Even when the tool is hidden, it works silently in the background. At some
regular intervals of time, it communicates with dotnetspider web services to
find if there is any new alerts created. If it finds a new alert, the tool
downloads the alerts and pops up a message displaying the alert. This message
will include a short description and a URL to click. By clicking the URL, you
can directly reach the dotnetspider page represented by the alert.
For example, when a new article is submitted in dotnetspider or when an answer
is posted for your question, your SpiderAlerts tool will immediately popup
alerting you to visit the page.
Web Services
A new alert is generated in dotnetspider.com when one of the following happens:
A new article is submitted
A new question is posted
An answer is posted for a question
A new job is posted
A news is posted
A new project is posted
(there are few more...)
Technically, each alert is a record in an 'Alert' database table. One of the
fields in the table represents the time the alert is generated. We expose one
method through web services to retrieve these alerts to the SpiderAlerts
application.
<WebMethod()> _ Public Function
GetAlerts(ByVal clientVersion As String, ByVal clientId As String, ByVal
lastCheckTime As DateTime) As DataSet
This method takes few parameters :
clientVersion - the version number of the client application. We use this
parameter to ensure that the correct version of the client application is used.
If an older, incompatible version of cliet is connected, we will throw an
exception.
clientId - A Guid that uniquely identifies each client. This is just for
statistical purposes to track how many clients are conncting.
lastCheckTime - This parameter indicates the last time when the client
downloaded the laerts. Only the alerts generated after the last check time is
retunred by this method call.
When a client (SpiderAlerts tool) calls this web service method, it returns all
new alerts as a DataSet.
Sample web services
If you do not have internet connection in your development computer, you can
setup your own web services so that you can test the SpiderAlerts application.
To setup the sample webservices in your development machine, download the web
service source code from the link in the top of this page. Extract the zip file
to a folder in your machine. Right click on the folder 'AlertWebServices' and
select the 'Properties'. Choose the 'Web Sharing' tab. Select the option 'Share
this folder' and Save. (This step changes this folder as a virtual folder so
that you can open it as a web application.)
Double click on the solution name 'AlertWebServices.sln' to open the sample
webservices solution. Open the web.config file and edit the key 'AlertsDsn' to
make sure the database connection string points to the correct location of
database in your machine. The database file is located in thesame folder where
you have the solution.
Now build the solution. Once you compile it, you can open the URL
http://localhost/AlertWebServices/default.aspx in your browser. Create couple
of new sample alerts by following the link 'Create New Alert' in the above web
page.
Create an application to test the web services
Instead of 'SpiderAlerts' tool, you can write your own .NET application to
retrieve the alerts. To do this, follow the easy steps below:
Create a new Windows application (C# or VB.NET)
Drag and Drop a DataGrid control to the default Form (The default name for the
datagrid will be DataGrid1)
Drag and drop a button control to the form.
Add a web reference to the dotnetspider web services. (Go to the solution
explorer, right click on the 'References' section under your project name and
select 'Add Web Reference'
In the dialog box to add web reference, specify the URL as http://localhost/AlertWebServices//spideralerts.asmx
and press 'Go'
If it does not give any errors, press 'Add Reference' to add a web reference to
the web services.
Once you have added a web reference to the web services, you can instantiate an
object of the web service class and call the methods.
Double click on the button control in your sample application to add an event handler for the
Button click event
Add the following code :
Dim service As New localhost.SpiderAlerts
Dim ds As DataSet = service.GetAlerts("", "", DateTime.Now.AddDays(-30))
DataGrid1.DataSource = ds
The above code will retrieve the alerts from the webservices and bind the
results to the data grid. If you run the application, you can see the data grid
displaying the results from the web services, everytime you click the button.
The result data set from the webservies contains additional information like
Server time etc. The data grid will display this information also. If you want
to see only the Alerts in the grid, bind the grid to the first table in the
dataset as shown below:
Dim service As New localhost.SpiderAlerts
Dim ds As DataSet = service.GetAlerts("", "", DateTime.Now.AddDays(-30))
DataGrid1.DataSource = ds.Tables(0)
Download real alerts from dotnetspider web services
If you are connected to internet, you can change the web reference in your test application to point to the
dotnetspider web services and download the real alerts.
Go back to the sample windows application you created. Remove the
web reference to your local webservices and add a new web reference to the URL
http://www.dotnetspider.com/services/SpiderAlerts.asmx. Now run your
application and you can see your data grid is displaying the real alerts from
dotnetspider.
SpiderAlerts Tool
SpiderAlerts tool works the same way the sample windows application you have
created. Some of the additional features of the SpiderAlerts tools is below:
SpiderAlerts tool has a timer control, which automatically call the web services
to retrieve the latest alerts. You do not need to press any button to retrieve the alerts.
This tool saves the 'Last Retrieve Time' in Isolated Storage. The web method is called
with this value as a parameter so that it need to download only the new alerts each time.
All downloaded alerts are stored in Isolated Storage so that it can still show you the already
downloaded alerts even if you restart the computer.
The actual SpiderAlerts tool supports posting answers to the alerts of type 'Question'. When a user
posts a question in dotnetspider.com, you will get an alert and you can post an answer directly from the
SpiderAlerts tool. But this feature is disabled in source code version for security reasons.
This tool allows you to view one alert at a time and you can press Next/Previous buttons to
navigate between alerts.
You can delete all downloaded alerts from Isolate Storage by clicking the menu item 'Delete All Alerts'.
When you minimize the application, the application disappears from screen and a small icon appears in the
system tray. You can double click the icon in system tray to reactivate the tool.
To close the tool, you must right click on the icon in system tray and select 'Close'.
You can select one or more alert types and 'block' it. If an alert type is blocked, all alerts of that
type will be hidden from the user. (All alerts are still in the isolated storage. When displayed to the user,
it is just filtered out.)
NOTE: SpiderAlerts tool uses Isolated Storage which is a new feature in .NET. If you have version 1.0
of .NET, this tool will not work.
You can extend your sample application to have all features of SpiderAlerts tool. Refer to the source
of SpiderAlerts tool and try to add all those features to your own test application. If you have any
questions, please use the feedback link below to post questions.
 Attachments
8--121618--SpiderAlertSetup.msi (8--121618--SpiderAlertSetup.msi)8--121619--SpiderAlerts.zip (8--121619--SpiderAlerts.zip)8--121619--AlertsWebServices.zip (8--121619--AlertsWebServices.zip)
8--121620--alert.gif
8--121620--reference.jpg
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| Author: Vasu Reddy | Member Level: Silver | Revenue Score:  |
Hi Tony
nice code na
thanq for posting this code.
Regards
srinivas.d
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| Author: jignesh | Member Level: Bronze | Revenue Score: |
its improve knolange of web application.
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| Author: Nushrat ali | Member Level: Bronze | Revenue Score: |
Hi Tony
Its really wonderfull
keep posting this kind of a work.
really helpful code assignment
Thank you very much for posting
Nushrat Tyagi
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| Author: ketan Italiya | Member Level: Gold | Revenue Score: |
hie,
nice code....thanks
Regards
ketan
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| Author: Bunty | Member Level: Gold | Revenue Score: |
Hi,
Really ausum piece of code.
Very good to start on .Net.
Keep posting such valuable code.
Thanks for sharing your knowledge.
Thanks and Regards
S.S.Bajoria
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| Author: siva | Member Level: Gold | Revenue Score: |
Hi,
Its really nice. I would like learn such type of things.
It will be greatful for me to send the files.
Thanks Rakesh,
Siva Sreenath
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| Author: Sonia sardana | Member Level: Gold | Revenue Score: |
hello sir , As i m fresher in C#,many of mine concepts got clear thru ur project...Sir can u plz give me ASP.net project along with specifications,Cz i m very keen to developed it..Just give me the project...Cz i m working as vb.net developer, I do not have the idea if ASP.Net project..can u plz help me on this matter!!!..If you can,plz reply me on mine id
sonia.sardana@yahoo.co.in
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