ASP.Net/ADO.net Database/Query
Read data from database in asp dropdownlist selection changed event (C#)
<%@ Page language="c#" src="AuthorBrowser.aspx.cs" AutoEventWireup="false" Inherits="AuthorBrowser" %>
<HTML>
<body>
<form id="Form1" method="post" runat="server">
<asp:label id="Label1" style="Z-INDEX: 105; LEFT: 32px; POSITION: absolute; TOP: 24px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="181px" Height="20px"> Select Author:</asp:label><asp:label id="lblResults" style="Z-INDEX: 106; LEFT: 32px; POSITION: absolute; TOP: 64px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="384px" Height="168px"></asp:label><asp:dropdownlist id="lstAuthor" style="Z-INDEX: 102; LEFT: 184px; POSITION: absolute; TOP: 20px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="171px" Height="22px" AutoPostBack="True"></asp:dropdownlist></form>
</body>
</HTML>
<%--
using System;
using System.Collections;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.OleDb;
public class AuthorBrowser : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Label Label1;
protected System.Web.UI.WebControls.Label lblResults;
protected System.Web.UI.WebControls.DropDownList lstAuthor;
private string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0; data source=" + System.Web.HttpContext.Current.Server.MapPath("EmployeeDatabase.mdb");
private void Page_Load(object sender, System.EventArgs e)
{
if (!this.IsPostBack)
{
FillAuthorList();
}
}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
InitializeComponent();
base.OnInit(e);
}
private void InitializeComponent()
{
this.lstAuthor.SelectedIndexChanged += new System.EventHandler(this.lstAuthor_SelectedIndexChanged);
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
private void FillAuthorList()
{
lstAuthor.Items.Clear();
// Define the Select statement.
// Three pieces of information are needed: the unique id,
// and the first and last name.
string selectSQL;
selectSQL = "SELECT FirstName, LastName, ID FROM Employee";
// Define the ADO.NET objects.
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(selectSQL, con);
OleDbDataReader reader;
// Try to open database and read information.
try
{
con.Open();
reader = cmd.ExecuteReader();
// For each item, add the author name to the displayed
// list box text, and store the unique ID in the Value property.
while (reader.Read())
{
ListItem newItem = new ListItem();
newItem.Text = reader["LastName"] + ", " + reader["FirstName"];
newItem.Value = reader["ID"].ToString();
lstAuthor.Items.Add(newItem);
}
reader.Close();
}
catch (Exception err)
{
lblResults.Text = "Error reading list of names. ";
lblResults.Text += err.Message;
}
finally
{
con.Close();
}
}
private void lstAuthor_SelectedIndexChanged(object sender, System.EventArgs e)
{
// Create a Select statement that searches for a record
// matching the specific author id from the Value property.
string selectSQL;
selectSQL = "SELECT * FROM Employee ";
selectSQL += "WHERE ID=" + lstAuthor.SelectedItem.Value + "";
// Define the ADO.NET objects.
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(selectSQL, con);
OleDbDataReader reader;
// Try to open database and read information.
try
{
con.Open();
reader = cmd.ExecuteReader();
reader.Read();
lblResults.Text = "<b>" + reader["LastName"];
lblResults.Text += ", " + reader["FirstName"] + "</b><br>";
lblResults.Text += "ID: " + reader["ID"] + "<br>";
reader.Close();
}
catch (Exception err)
{
lblResults.Text = "Error getting author. ";
lblResults.Text += err.Message;
}
finally
{
con.Close();
}
}
}
--%>
<A href="http://www.nfex.ru/Code/ASPDownload/EmployeeDatabase.zip">EmployeeDatabase.zip( 10 k)</a>
Read data from database in code behind (C#)
<%@ Page language="c#" src="AuthorBrowser.aspx.cs" AutoEventWireup="false" Inherits="AuthorBrowser" %>
<HTML>
<body>
<form id="Form1" method="post" runat="server">
<asp:label id="Label1" style="Z-INDEX: 105; LEFT: 32px; POSITION: absolute; TOP: 24px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="181px" Height="20px"> Select Author:</asp:label><asp:label id="lblResults" style="Z-INDEX: 106; LEFT: 32px; POSITION: absolute; TOP: 64px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="384px" Height="168px"></asp:label><asp:dropdownlist id="lstAuthor" style="Z-INDEX: 102; LEFT: 184px; POSITION: absolute; TOP: 20px" runat="server" Font-Size="X-Small" Font-Names="Verdana" Width="171px" Height="22px" AutoPostBack="True"></asp:dropdownlist></form>
</body>
</HTML>
<%--
using System;
using System.Collections;
using System.ruponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.OleDb;
public class AuthorBrowser : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Label Label1;
protected System.Web.UI.WebControls.Label lblResults;
protected System.Web.UI.WebControls.DropDownList lstAuthor;
private string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0; data source=" + System.Web.HttpContext.Current.Server.MapPath("EmployeeDatabase.mdb");
private void Page_Load(object sender, System.EventArgs e)
{
if (!this.IsPostBack)
{
FillAuthorList();
}
}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
InitializeComponent();
base.OnInit(e);
}
private void InitializeComponent()
{
this.lstAuthor.SelectedIndexChanged += new System.EventHandler(this.lstAuthor_SelectedIndexChanged);
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
private void FillAuthorList()
{
lstAuthor.Items.Clear();
// Define the Select statement.
// Three pieces of information are needed: the unique id,
// and the first and last name.
string selectSQL;
selectSQL = "SELECT FirstName, LastName, ID FROM Employee";
// Define the ADO.NET objects.
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(selectSQL, con);
OleDbDataReader reader;
// Try to open database and read information.
try
{
con.Open();
reader = cmd.ExecuteReader();
// For each item, add the author name to the displayed
// list box text, and store the unique ID in the Value property.
while (reader.Read())
{
ListItem newItem = new ListItem();
newItem.Text = reader["LastName"] + ", " + reader["FirstName"];
newItem.Value = reader["ID"].ToString();
lstAuthor.Items.Add(newItem);
}
reader.Close();
}
catch (Exception err)
{
lblResults.Text = "Error reading list of names. ";
lblResults.Text += err.Message;
}
finally
{
con.Close();
}
}
private void lstAuthor_SelectedIndexChanged(object sender, System.EventArgs e)
{
// Create a Select statement that searches for a record
// matching the specific author id from the Value property.
string selectSQL;
selectSQL = "SELECT * FROM Employee ";
selectSQL += "WHERE ID=" + lstAuthor.SelectedItem.Value + "";
// Define the ADO.NET objects.
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(selectSQL, con);
OleDbDataReader reader;
// Try to open database and read information.
try
{
con.Open();
reader = cmd.ExecuteReader();
reader.Read();
lblResults.Text = "<b>" + reader["LastName"];
lblResults.Text += ", " + reader["FirstName"] + "</b><br>";
lblResults.Text += "ID: " + reader["ID"] + "<br>";
reader.Close();
}
catch (Exception err)
{
lblResults.Text = "Error getting author. ";
lblResults.Text += err.Message;
}
finally
{
con.Close();
}
}
}
--%>
<A href="http://www.nfex.ru/Code/ASPDownload/EmployeeDatabase.zip">EmployeeDatabase.zip( 10 k)</a>
