ASP.NET Tutorial/ADO.net Database/OleDbDataReader
Iterating Through A OleDbDataReader
<source lang="csharp">
<%@ Page Language="C#" %> <%@ import Namespace="System.Data" %> <%@ import Namespace="System.Data.OleDb" %> <script runat="server">
void Page_Load(object sender, EventArgs e)
{
string ConnectionString = Convert.ToString(ConfigurationSettings.AppSettings["AccessConnectString"]);
string CommandText = "SELECT AuthorName, AuthorCity, AuthorContact_Email, AuthorWebsite FROM Author";
OleDbConnection myConnection = new OleDbConnection(ConnectionString);
OleDbCommand myCommand = new OleDbCommand(CommandText, myConnection);
try {
myConnection.Open();
OleDbDataReader myReader = myCommand.ExecuteReader();
if (myReader.HasRows) {
while (myReader.Read())
{
for (int i=0; i<=(myReader.FieldCount-1); i++)
{
if (myReader.IsDBNull(i))
{
Label1.Text += "Warning: Field " + i + " is NULL.";
}
}
Author p = new Author();
p.Name = myReader.GetString(0);
p.City = myReader.GetString(1);
p.Email = myReader.GetString(2);
p.Website = myReader.GetString(3);
Label1.Text += p.ToString();
}
}
else
{
Label1.Text = "No rows returned";
}
if (!(myReader.IsClosed))
{
myReader.Close();
}
} catch (Exception ex)
{
throw (ex);
}
finally
{
myConnection.Close();
}
}
public class Author
{
public string Name;
public string City;
public string Email;
public string Website;
public Author()
{}
public string ToString()
{
string description = "";
description = "Name : " + this.Name + "
";
description += "City : " + this.City + "
";
description += "Contact : <a href=mailto:" + this.Email + ">" + this.Email + "</a>
";
description += "Homesite : <a href="" + this.Website + "">" + this.Website + "</a>
";
return description;
}
}
</script> <html> </title> </head> <body>
<asp:Label id="Label1" runat="server"></asp:Label>
</body> </html> File: Web.config <configuration>
<appSettings>
<add key="AccessConnectString"
value="Provider=Microsoft.Jet.OLEDB.4.0; Data Source=Books.mdb;" />
</appSettings>
</configuration></source>
