Open Visual Studio and follow the below steps
to open a web application.
The
Steps are:-
1) Go to Menu Bar and Click on “File” Menu.
2) Click on “New”.
3) Click on “Project”. Then a window will appear.
4) Click on Visual C# and expand it.
5) Select “web” option from Visual C#.
6) Select ASP.NET Web Application.
7) Give the name of the web application and also the directory to store the web application.
8) Then a solution is created for that web application.
1) Go to Menu Bar and Click on “File” Menu.
2) Click on “New”.
3) Click on “Project”. Then a window will appear.
4) Click on Visual C# and expand it.
5) Select “web” option from Visual C#.
6) Select ASP.NET Web Application.
7) Give the name of the web application and also the directory to store the web application.
8) Then a solution is created for that web application.
Agenda:
The main agenda of this
application is to save, update, delete student name, class and whenever we
saved the record that student name must present in a dropdown list. When we
select student name in dropdown list, then student name, class must be
displayed in the textboxes present.
using
System;
using
System.Data;
using
System.Data.SqlClient;
using
System.Web.UI.WebControls;
namespace
StudentDetails
{
public partial class _Default : System.Web.UI.Page
{
//below line
is used to establish connection to database
SqlConnection
con = new SqlConnection("Data Source=*******; Initial Catalog=********; user
id=********; password=******");
protected
void Page_Load(object
sender, EventArgs e)
{
//we have
to write !IsPostBack in page load so that when the page is loaded for first
time,the method will be called.
if
(!IsPostBack)
{
//here
the method dropdownddl will be called only ones,that is at the time of page
loading
dropdownddl();
}
}
public void
dropdownddl()
{
try
{
//dsdropdownddl
is the object created for the DataSet
DataSet
dsdropdownddl = new DataSet();
//Opening
the Sql Server Connection
con.Open();
//ad
is the object created for SqlDataAdapter to execute the sql command
SqlDataAdapter
ad = new SqlDataAdapter("select * from Studentdetails1tier",
con);
//here
data is filled in the DataSet
ad.Fill(dsdropdownddl);
ddlSelectstudent.DataSource =
dsdropdownddl;
ddlSelectstudent.DataTextField
= "StudentName";
ddlSelectstudent.DataValueField
= "S_ID";
ddlSelectstudent.DataBind();
ddlSelectstudent.Items.Insert(0, new ListItem("--Select--",
"0"));
//Closing
the Sql Server Connection
con.Close();
}
catch
(Exception ex)
{
}
}
protected
void ddlSelectstudent_SelectedIndexChanged(object sender, EventArgs
e)
{
//we
select the dropdown list value and convert it into integer and assign the value
to S_ID
int
S_ID = Convert.ToInt32(ddlSelectstudent.SelectedValue);
//Opening
the Sql Server Connection
con.Open();
//creating
the object for SqlCommand and writing the select query
SqlCommand
studentcmd = new SqlCommand("select StudentName,Class from Studentdetails1tier
where S_ID=" + S_ID, con);
//creating
object for SqlDataAdapter and reading data from SqlCommand
SqlDataAdapter
studentda = new SqlDataAdapter(studentcmd);
//creating
an object for DataSet
DataSet
studentds = new DataSet();
//Filling
data in DataSet from dataAdapter
studentda.Fill(studentds);
//Closing
the Sql Server Connection
con.Close();
//to show
the student name and class for particular Student name
txtStudentname.Text =
studentds.Tables[0].Rows[0][0].ToString();
txtClass.Text =
studentds.Tables[0].Rows[0][1].ToString();
}
void
Clear()
{
try
{
//dropdown
method is called to bind the student name in the dropdown list
dropdownddl();
//After
saving the data,to show the data in the textboxes as empty we place null in
both the Textboxes
txtStudentname.Text = null;
txtClass.Text = null;
}
catch
(Exception ex)
{
}
}
protected
void btnSave_Click(object
sender, EventArgs e)
{
try
{
//here
the object is created for SqlCommand and Insert Query is written in the object
to insert data in the Sql Server
SqlCommand
cmdsave = new SqlCommand("INSERT INTO Studentdetails1tier VALUES('"
+ txtStudentname.Text + "','" +
txtClass.Text + "')", con);
//Opening
a connection for Sql Server
con.Open();
//Executing
the Insert Query
cmdsave.ExecuteNonQuery();
//Closing
the Sql Server Connection
con.Close();
//Clear
method is called
Clear();
}
catch
(Exception ex)
{
}
}
protected
void btnUpdate_Click(object
sender, EventArgs e)
{
try
{
//creating
object for SqlCommand and writing Update query
SqlCommand
cmdupdate = new SqlCommand("UPDATE Studentdetails1tier SET StudentName='"
+ txtStudentname.Text + "',Class='"
+ txtClass.Text + "' WHERE S_ID='"
+ Convert.ToInt32(ddlSelectstudent.SelectedValue)
+ "'", con);
//Opening
a connection for Sql Server
con.Open();
//Executing
the Update query
cmdupdate.ExecuteNonQuery();
//Closing
the Sql Server Connection
con.Close();
//calling
clear method
Clear();
}
catch
(Exception ex)
{
}
}
protected
void btnDelete_Click(object
sender, EventArgs e)
{
try
{
//creating
object for SqlCommand and writing Delete query
SqlCommand
cmddelete = new SqlCommand("DELETE FROM Studentdetails1tier WHERE S_ID='"
+ Convert.ToInt32(ddlSelectstudent.SelectedValue)
+ "'", con);
//Opening
a connection for Sql Server
con.Open();
//Executing
the Delete query
cmddelete.ExecuteNonQuery();
//Closing
the Sql Server Connection
con.Close();
//calling
clear method
Clear();
}
catch
(Exception ex)
{
}
}
protected
void btnCancel_Click(object
sender, EventArgs e)
{
//calling
clear method
Clear();
}
}
}
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