Computer Programming

Friday, September 20, 2013

September 20, 2013

How to remove selected item from ListBox in ASP.NET

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

   protected void Button1_Click(object sender, EventArgs e)
   {
   if (ListBox1 .Items .Count !=0)
   {
   ListBox1.Items.RemoveAt(ListBox1.SelectedIndex);
   }
   }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <asp:ListBox ID="ListBox1" runat="server" Height="142px" Width="117px">
   <asp:ListItem>APPLE</asp:ListItem>
   <asp:ListItem>MANGO</asp:ListItem>
   <asp:ListItem>ORANGE</asp:ListItem>
   </asp:ListBox>
   <br />
   <br />
   <asp:Button ID="Button1" runat="server" onclick="Button1_Click"
   Text="REMOVE SELECTED" Width="143px" />
   </div>
   </form>
</body>
</html>

Output

ASP.NET

September 20, 2013

Clear or Remove item from DropDownList in ASP.NET

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

   protected void Button1_Click(object sender, EventArgs e)
   {
   DropDownList1.Items.Clear();
   }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <asp:DropDownList ID="DropDownList1" runat="server" Height="47px" Width="171px">
   <asp:ListItem>Apple </asp:ListItem>
   <asp:ListItem>Mango</asp:ListItem>
   <asp:ListItem>Orange</asp:ListItem>
   </asp:DropDownList>
   <br />
   <br />
   <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="CLEAR"
   Width="88px" />
   </div>
   </form>
</body>
</html>

Output

ASP.NET

September 20, 2013

How to create User Profiles in ASP.NET

You have now been familiarized with the basic concept of personalization. In ASP.NET websites can be personalized by using the concept of user profiles and themes. Themes are used to enhance the look and feel of a Web page , but are incapable of storing and using the information of a specific user for personalization. In ASP.NET you can use the concept of user profiles to display information of a specific user for personalization. For example , if a user revisits a shopping website , the details of the items purchased in the either visit can also be displayed.
A user profile is a collection of various properties that describes the information you want to store for a specific user. You can store the properties associated with a user in a user profile. The Data that is stored in a profile can be accessed programmatically.

Lets take an Example How to create User Profiles in ASP.NET

Step-1 : Write some properties under profile tag in web.config file

<system.web>
   <anonymousIdentification enabled ="true"/>
   <profile>
   <properties >
   <add name ="SName" allowAnonymous ="true" />
   <add name ="CName" defaultValue ="ASP.NET" allowAnonymous ="true" />
   <add name ="RollNo" defaultValue ="101" allowAnonymous ="true" />
   </properties>
   </profile>
   <compilation debug="false" targetFramework="4.0" />
   </system.web>

Step-2: Write this code under ".aspx" page

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

   protected void Button1_Click(object sender, EventArgs e)
   {
   Profile.SName = TextBox1.Text;
   Profile.CName = TextBox2.Text;
   Profile.RollNo = TextBox3.Text;
   }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   Welcome User

   <br />
   Student Name :<%= Profile .SName %>
   <br />
   Course Name :<%= Profile .CName %>
   <br />
   Student RollNo:<%= Profile .RollNo %>
   <br />
   Enter Student Name :
   <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
   <br />
   Enter Course Name :
   <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
   <br />
   Enter Roll No :         
   <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
   <br />
   <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Submit" />

   </div>
   </form>
</body>
</html>

Default value Output
1. Default value show in output first

2. Enter value show in output

3. Close your current output browser window and re-run your application, profile save the variable value

Thursday, September 19, 2013

ASP.NET

September 19, 2013

Page Life Cycle in ASP.NET

When an ASP.NET page runs, the page goes through a life cycle in which it performs a series of processing steps. These include Initialization, Instantiating controls, restoring and maintaining state, running event handler code, and rendering.

(1)Page Initialization = Page_Init
(2)View State Loading = LoadViewState
(3)PostBack data processing = LoadPostData
(4)Page Loading = Page_Load
(5)PostBack Change Notification = RaisePostDataChangedEvent
(6)PostBack Event Handling = RaisePostBackEvent
(7)Page Pre Rendering Phase = Page_PreRender
(8)View State Saving = SaveViewState
(9)Page Rendering = Page_Render
(10)Page Unloading = Page_UnLoad

ADO.NET Binding c# database DataGridView Windows Forms

September 19, 2013

How to Bind DataGridView with DataSet in Windows Forms: ADO.NET

In our previous post, I have described about the ways to bind datagridview in windows forms. The first way is to bind the datagridview with dataset and show the data of a table in the gridview. Here is the syntax of binding in c#:
dataGridView.DataSource= ”DataSet Name”;
dataGridView.DataMember=”Table Name”;

Now the time is to perform this code with our existing dataset and table. Drag-n-drop a datagridview on the window and write the following c# code in our form’s constructor:

SqlConnection connection = new SqlConnection();
connection.ConnectionString = "Data Source=(LocalDb)\\v11.0; Initial Catalog=StockDb; Integrated Security=True";
connection.Open();

SqlCommand command = new SqlCommand("select * from Groups", connection);

DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(command);
da.Fill(ds);

dataGridView1.DataSource = ds;
dataGridView1.DataMember = ds.Tables[0].ToString();

In the above code, first four lines are same as written in executing sql statements. Fifth line will create a new object of DataSet. Six line will create an object of SqlDataAdapter class which will create an adapter with specified command object.

Next line tell us to fill the dataset with the adapter, which contains all the rows returning by the command object.

Now the last two lines are used to specify the data source of datagridview and the table which will be bind to. When we run the code a window will show with a datagridview containing all the returning rows as shown in following image:

How to bind DataGridView with dataset in Windows Forms ADO.NET

c# database SQL-SERVER SqlDataReader

September 19, 2013

How to Execute Parameterized SQL Statements: ADO.NET

As we know, SQL statements can be of simple type or may be parameterized. The parameterized query contains some parameters, which may be accepted through object of SqlParameter class. SqlParameter class is used to create the parameters used by the command object to execute the Sql queries.
Write the following code to select a record from the table groups which has a given name. The name is passed by the parameter i.e. Sql Parameter.

SqlConnection connection = new SqlConnection();
connection.ConnectionString = "Data Source= (LocalDb)\\v11.0; Initial Catalog=StockDb; Integrated Security=True";
connection.Open();
SqlCommand command = new SqlCommand("select * from Groups where code=@code", connection);
command.Parameters.AddWithValue("@code", 04);
SqlDataReader dr = command.ExecuteReader();

Look out the command object which have a variable name @code. It is the syntax of parameter used. In the next line, the parameter is added by using the function AddWithValue(). This method takes two parameter i.e. one for variable name (same as used in command object) and the second one is its value.

Now when we execute this code, a single record having code = 04 will be returned and can be accessed by data reader object dr.

We can check the rows as the same procedure as in previous post.

c# database SQL-SERVER SqlDataReader

September 19, 2013

How to Execute SQL Statements: ADO.NET

We have learnt about ADO.NET object model. In that article we have created a SQL connection, open that connection and close that connection. To execute the SQL statements, we have to write them in between the open and close method of the above connection.

So to execute the SQL statement we have to, first create the connection, open that, write some code which will be executed and at the last execute it with ExecuteReader() method of SQLCommand class.

SqlCommand class is used to specify the Sql statement to be executed and the connection that need to be used. It can also be used to execute stored procedures. Following code will used to execute Sql statement in a command object:

SqlConnection connection = new SqlConnection();
connection.ConnectionString = "Data Source=(LocalDb)\v11.0; Initial Catalog=StockDb; Integrated Security=True";
connection.Open();
SqlCommand command = new SqlCommand("select * from Groups", connection);
SqlDataReader dr = command.ExecuteReader();

In the above code, when SqlCommand object will create, an object of SqlDataReader have been also created. And it is initialized with the function ExecuteReader(). Now all the data can be accessed one by one through dr object, one by one.

When we check the dataReader object through the breakpoint then there are some rows, as shown in following image: