ASP.Net C# Passing values from a grid view

Passing values from a grid view (ASP.net C#)

When working in asp.net, I usually use gridViews to show and manipulate data. Well, it’s a good clean and easy way to get ad manipulate data from a db.

But suppose you select a value from a gridView and when you select it say… some sort of a key, it should pass into another page.

In this tutorial we will look at creating a simple data base table, creating a connection, getting data to a grid view and passing it to another page :D

Believe it or not, it’s not as hard as it sounds.

Well, first things first

Create a data base using ms sql server management studio express (wow that’s a long name …)

Go to the MSSMSE, log in to it and by right clicking the Databases folder, create a new database called

myTesting

now you will be able to see the newly created database. 

Select it and then click on the new query so that you can write sql for the database :D

Then you can write the following queries,

/*this is how we comment in sql*/

create table sampleTable(

id  int primary key identity (0, 1),

name varchar(100),

age int,

country varchar(100)

)

the create table  statement will create a table with the name sampleTable with attributes id, name,

age and country. In the table you can see data types as int and varchar.

id is set as the primary key

identity is a special feature in mssql server (as I remember, some of the other databases doesn't support that). It is defined as identity (SEED, INCREMENT). SEED means the starting value and INCREMENT means the value that it is incremented from. With this, we can make the identity auto increment.

run this query and see if the table is working properly, you will see an empty table

select * from sampleTable

Now insert some values in to the table....

note that I'm not inserting any values in to the id column because it will auto increment.

insert into sampleTable(name, age, country) values ('sampleName0', 13, 'sampleCountry0')

insert into sampleTable(name, age, country) values ('sampleName1', 16, 'sampleCountry1')

insert into sampleTable(name, age, country) values ('sampleName2', 17, 'sampleCountry2')

insert into sampleTable(name, age, country) values ('sampleName3', 17, 'sampleCountry3')

insert into sampleTable(name, age, country) values ('sampleName4', 18, 'sampleCountry4')

insert into sampleTable(name, age, country) values ('sampleName5', 19, 'sampleCountry5')

insert into sampleTable(name, age, country) values ('sampleName6', 13, 'sampleCountry6')

Run this query and you will see all the data in the table

select * from sampleTable

Run this and you will see only the name, age and country columns from sampleTable

select name, age, country from sampleTable

Run this and you will see all rows from the table where the age is greater than 17

select * from sampleTable

where age > 17

( if you don’t know how to run a query, all you have to do is highlight the relevant part of the query, and press execute… for example, if you want to run a select query , highlight select * from sampleTable and the press execute)

Now that creation of tables is complete, let us go to visual studio.

Start a new web site in C#, because I am bored, I keeping the name as the default one "WebSite1"

Now make a new page in the web site,

right click on the root that is in shown in the solution explorer, 

select Add New Item 

select Web Form (make sure you select visual c#, in Installed Templates)

Now change the name to TestingForm.aspx

click Add 

Now you will be able to see the page in the solution explorer.

ok, so lets do some cool stuff.

Now add a  gridView controller to the to the page.

(well you can do it in design or source view)

Now it should look like this in the design view.

Now, click on that > like thing in the data gridView and in the choose data source drop select <new data source >

select SQL data base

make the datasoruce name as appropriate.

select new connection 

select Microsoft SQL Server and press continue 

Now in the new window, for the server name TYPE, localhost\SQLEXPRESS ( server and instance name, change as appropriate ).

after entering the server name is entered, select the database. now press Test Connection

If the connection is successful, press OK

now you will be able to see the data connection press NEXT

Keep notice the data connection name and press Next

Leave them as they are and press next

press test query and you will see all the data that was inserted in to the db, press finish

Now run the application by right clicking and selecting view in browser ...

notice all the data is visible in the grid view

now go back to the TestingForm and in the gridView go to edit columns

add a HyperLinkField

Give it a name

Now, lets create a new web form called TestingForm2 , we will pass the selected gridView value from the TestingForm to this TestingForm2.

You can see the new page in the solution explorar

Now add a new Label to the newly created TestingForm2

Now lets get back to the TestingForm.aspx and edit that gridView, go inside it and select the link field and add the new TestingForm2.aspx  the NavigateURL

Select the TestingForm2.aspx so it is added as the navigation url

See  .... you can see the TestingForm2.aspx in the NavigateURL, press OK

Now, you can see the links in blue color that means, they are active so they can navigate to another page.

Right click the TestingForm and select view in browser and check out the page ...

Press the Go link in TestingForm and you will notice that you have navigated to TestingForm2

Now in the TestingForm2 you can only see the label, no values passed yet

Now go back to the TestinForm.aspx and edit the gridView as the following.
We edited the NavigateURL before,
now
set DataNavigateUrlFields to "id"
and set DataNavigateUrlFormatString to TestingForm2.aspx?id={0}
that is
<place to navigate>?<passingvalue>={0}

Now go to the code behind of the TestingForm2

not set the Label1's text to the values that were passed to the query string from the other page.
id is the identifying value we set ( you should see the code view of the gridView to get a better understanding of this).

Now run the page again
and press the Go link

you can see the value passed to the other page

WOW that was long ... if this works, help ur self to a nice cup of tea :D :D

Hope this helps,
Cheers

MS SQL server default instance

How to install SQL Severver Management Studio Express
(using a proper server instance to connect to the server)

Before installing this make sure you have installed the visual studio pack that was downloaded from the MSDN site or the dreamspark site.

go and search in the google for sql server management studio express and you will be able to download it easily and for free ( EXPRESS editions are free)

I am not going to talk about downloading the software much. Its not that difficult

well then install it keeping everything as default, of course change if necessary, make sure to remember the server instance name.  

well after you install the software, when you run it for the first time, you will see a window like this,

you should enter the server name and instance.

Soooo, if you haven't changed any thing in the installation and kept every thing as default, the default server instance shout be SQLEXPRESS

so you should put, <server name>\<server instance>

localhost is when the server is in your own machine 

so the server name is 

localhost\SQLEXPRESS

then press connect

after you connect to the database server it should give a window as below.

 If you like to create a new database, right click on the Databases folder and create a new database

hope this helps
cheers

ASP.Net C# session object

How to pass values to a session (ASP.net C#)

When working on ASP.net web pages or any other web programming for that matter, there comes a point we need to pass values or objects between web pages.

There are several ways of doing this, as examples

We can use the view state string that passes values as a string in the page or

We can use a cookie which is not more than a text file that stores data in the client side computer or

We can use a session variable.

In this tutorial we look at how to work with a session variable

All you have to do is, create a session variable, pass the values in to it and retrieve when necessary.

So here’s the way to do it :D

Creation of a session

Suppose there is an integer variable and you want to assign it to the session object.

//integer variable

int intVar = 10;

//below the int variable is assigned to the session

//remember you can even add an object to a session

//the <userID> is the session variable name and it is written within double quotes and it’s the name

//access the session object

Session[“userID”] = intVar;

Accessing the session variable

To check this, you should go to another page or some where

And in the code behind we can assess the variable using the following code.

Make sure you get the code working inside a page load method or something like that

//remember you have to cast it to an int type.

//if you passed another object, as an example a User type object, then cast it to User type

int passedVariable  = (int)Session[“userID”];

As an example of the usage of this ( in my opinion) we can create a session object in the log in page and pass it to the master page if we need to change the master page according to the authentication level and every time we need to check for authentication or authentication level, in every page load, check the session variable and see if its null or not.

If you want to log out set the session as null.

(Please note that this is one of the ways of doing it and it might not be the best way, if you have any better way of working with sessions or log ins please be kind enough to share them with me)

Hope that helps

Cheers

Restoring HP laptop to the factory state

Restoring your HP laptop to the factory state

(When boot loader is deleted, in other words  when F11 doesn't work)

NOTE 

I have written this tutorial in a way that some people might not understand, if you don't understand don't follow the tutorial because it might make your computer go to a state where you cannot use it at all.

Remember what ever you do, back up your data before starting the process

Background to the problem

After 2 sent backs costing almost a month my HP machine was finally repaired.

In the communication process I found out that, if you don't send the HP laptop in the original factory state, they will consider it as a breaking of warranty conditions (GREAT!!!).

So if you hadn't created recovery disks, and if you lost your boot loader because you installed another copy of windows or if you have installed linux (even Ubuntu with WUBI). Your boot up or recovery keys like F11 might not work. 

So, now you have to use the recovery partition to restore the machine to the factory settings, but how do you access the recovery partition ?

Well,

Strategy

The strategy here is to create a separate partition, copy the content of the recovery partition to the and set it as the ACTIVE partition, once you do that, it’ll make the computer boot from that partition, Thus making the recovery process start.

Necessary items

You will need a bootable windows CD or some sort of a boot up disk to go to a terminal (or a command prompt) remember, you can’t do this when you are inside windows, you have to boot from a separate disk.

Process

1.       Make sure all the folders are visible, if not go to folder options and make all the files even hidden files and machine files visible. (in your recovery partition otherwise how can you copy paste?)

2.       If you don’t already have a partition you have to create a new partition

3.       If you are using windows vista or 7

       right click on computerà manageàdisk management

4.       Using the disk management tool create a new partition large enough to keep the stuff of the recovery partition

5.       Now copy all the stuff of recovery partition to the newly created partition ( make sure they look exactly the same)

6.       Now, load the bootable disk and boot the computer using them ( a windows DVD or a boot disk)

7.       Go to a command prompt

8.       Now, what you have to do is find the find the relevant disk, find the relevant partition and make it active

9.       The commands you will be are the following

A.      diskpart ( this will move for the disk partitioning )

B.      list disk (displays a list of disks available)

C.      select disk 0 (use one of the numbers from list disk)

D.      list partition (displays a list of available partitions)

E.       list partition 1 (select the appropriate partition)

F.       active (this will make the partition active)

G.     exit ( exit from partition)

H.      exit ( exit from disk)

 10.       Now, just restart the computer and it will boot from the newly created active partition.

Hope this helps 

cheers