www.enaos.net code 398 PROGRAMMING ADO.NET in Font

Generator Code-39 in Font PROGRAMMING ADO.NET

CHAPTER 11 PROGRAMMING ADO.NET
Painting Code-39 In None
Using Barcode printer for Font Control to generate, create Code 39 image in Font applications.
www.OnBarcode.com
QR Code JIS X 0510 Creation In None
Using Barcode creator for Font Control to generate, create QR Code 2d barcode image in Font applications.
www.OnBarcode.com
cnn1.Open() Dim intMin As Integer = CInt(cmdMin.ExecuteScalar) Dim intMax As Integer = CInt(cmdMax.ExecuteScalar) If (CInt(strValue) < intMin Or CInt(strValue) > intMax) Then cnn1.Close() Return ("Value out of range") End If Catch ex As Exception cnn1.Close() Return (ex.Message) End Try Return ("Value in range") End Function
Paint Barcode In None
Using Barcode generator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Barcode Creator In None
Using Barcode generator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Returning a Value in a Web Application
Generate UCC - 12 In None
Using Barcode encoder for Font Control to generate, create GTIN - 12 image in Font applications.
www.OnBarcode.com
Encoding GTIN - 13 In None
Using Barcode maker for Font Control to generate, create EAN 13 image in Font applications.
www.OnBarcode.com
ADO.NET syntax follows the same conventions for web applications as for Windows applications. This section describes a web application with a single web page (Default.aspx) in a WebSite project that illustrates the basic principles for connecting to a data source and running a command against the data source. The two samples for this section illustrate how to connect to database files in the APP_Data folder of the WebCh11 website. I copied the Microsoft Access Northwind sample database file to the folder as well as the .mdf and .ldf files for the Northwind SQL Server sample database. Because the two code samples work with Access and SQL Server databases, the module behind the page begins with Imports statements for the System.Data.SqlClient and System.Data.OleDb namespaces. Figure 11-3 shows the Default.aspx web page from the Design tab of VWDE. Notice there are two Button controls one for making a connection to and using an Access database, and another for performing the same tasks for a comparable SQL Server Express database. The OleDbCommand object behind the Query Access button counts the number of rows in the Shippers table, and related code displays the result in a Label control. The text announcing that the connection is closed results from a My.Response.Write statement.
Paint Code 128B In None
Using Barcode printer for Font Control to generate, create Code 128 Code Set B image in Font applications.
www.OnBarcode.com
Encode Postnet In None
Using Barcode printer for Font Control to generate, create USPS POSTNET Barcode image in Font applications.
www.OnBarcode.com
Figure 11-3. Connecting to and using a database from a WebSite project uses the same ADO.NET syntax as from a Windows application project.
Code 39 Printer In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create Code 39 image in ASP.NET applications.
www.OnBarcode.com
Scan Code-39 In VS .NET
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
CHAPTER 11 PROGRAMMING ADO.NET
Code-39 Drawer In Visual Basic .NET
Using Barcode generator for .NET Control to generate, create Code 3/9 image in VS .NET applications.
www.OnBarcode.com
Recognizing ECC200 In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
The following listing shows the code in the Button1_Click procedure for Default.aspx. The code starts by declaring and instantiating an OleDbConnection object (cnn1) and an OleDbCommand object (cmd1). Next, the sample computes the path to the Northwind.mdb file in the project s APP_Data folder, and uses the path to help compute a connection string for the ConnectionString property of cnn1. The remaining code in the sample puts the cnn1 object to use with the cmd1 object. First, the code opens a connection to the Northwind.mdb file. Next, it specifies an OleDbCommand object (cmd1) that can count the rows in the Shippers table. Then, the code invokes the ExecuteScalar method for cmd1 to compute a count of the shippers and assigns the result to the Text property of the Label control. If the procedure ends normally, the code closes the cnn1 Connection object. Otherwise, the code writes a message about the reason the code does not end normally. Dim cnn1 As New OleDbConnection Dim cmd1 As New OleDbCommand 'Compute path to and create connection for Access database file Dim DSPath As String = _ My.Computer.FileSystem.CombinePath( _ Server.MapPath("/WebCh11/App_Data"), "Northwind.mdb") cnn1.ConnectionString = "Provider = Microsoft.Jet.OLEDB.4.0;" & _ "Data Source = " & DSPath 'Open connection, use it, close it Try cnn1.Open() cmd1.CommandText = "SELECT Count(*) FROM Shippers" cmd1.Connection = cnn1 Me.Label1.Text = "Number of Shippers: " & _ cmd1.ExecuteScalar().ToString Catch ex As Exception My.Response.Write(ex.Message) Finally cnn1.Close() My.Response.Write("Connection closed.") End Try The code for Button2_Click connects to the SQL Server Northwind database instead of the Access Northwind database. However, it computes the count of Shippers and displays its results in an identical fashion. If it were not for the Button2 Text property, you could not tell whether you were using SQL Server Express database files or an Access database file. The following excerpt from Button2_Click shows the part of this click procedure that is different from the one in Button1_Click. The excerpt starts by declaring and instantiating SqlConnection and SqlCommand objects instead of OleDbConnection and OleDbCommand objects. Next, the code computes the path to the Northwnd.mdf file instead of the Northwind.mdb file. Then, the code computes a connection string that ties the SQL Server Northwind database files to the .\sqlexpress SQL Server Express instance with integrated security.
EAN-13 Supplement 5 Encoder In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create GTIN - 13 image in ASP.NET applications.
www.OnBarcode.com
PDF 417 Drawer In Java
Using Barcode printer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
PDF-417 2d Barcode Creation In Visual Basic .NET
Using Barcode generation for Visual Studio .NET Control to generate, create PDF 417 image in .NET framework applications.
www.OnBarcode.com
EAN / UCC - 13 Encoder In Visual Studio .NET
Using Barcode encoder for Reporting Service Control to generate, create EAN / UCC - 13 image in Reporting Service applications.
www.OnBarcode.com
Printing UCC.EAN - 128 In None
Using Barcode drawer for Microsoft Excel Control to generate, create UCC.EAN - 128 image in Office Excel applications.
www.OnBarcode.com
Generate 1D In Visual Basic .NET
Using Barcode generation for VS .NET Control to generate, create Linear 1D Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Code 39 Creation In None
Using Barcode generator for Online Control to generate, create ANSI/AIM Code 39 image in Online applications.
www.OnBarcode.com
Barcode Scanner In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.