.net barcode reader dll CREATING WEB-BASED TESTWARE in Font

Creator PDF 417 in Font CREATING WEB-BASED TESTWARE

CHAPTER 9 CREATING WEB-BASED TESTWARE
Generating PDF417 In None
Using Barcode drawer for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
Creating USS Code 39 In None
Using Barcode generation for Font Control to generate, create Code-39 image in Font applications.
www.OnBarcode.com
objComm.CommandType = Data.CommandType.Text objComm.CommandText = strInsert 'Response.Write(objComm.CommandText.ToString) 'Open the connection and run the command Try objCon.Open() objComm.ExecuteNonQuery() objCon.Close() Response.Redirect("Default.aspx") Catch ex As Exception Response.Write(ex.ToString) End Try End Sub Looking at the Data Source property in Listing 9-9, you will notice that it points to an .mdb file on the hard drive. Although it could be in any folder, we have placed this file on the C:\ drive just to make the path easy to type. Next, we set the provider (which acts like a driver) to use the Microsoft Jet data engine. This is the provider used in a number of Microsoft products including Access and Excel. After that, we set the Password to blank, which is the default in Access, and specify row-level locking so that other users of the web application will not find the entire table locked when one user runs the Insert command. Listing 9-9 is using ADO.NET 2.0, which is the newest version at the time of this writing. This version has a number of new features that makes connecting to a database easier than ever. One of these is the new OleDbConnectionStringBuilder class. This class allows you to make connection strings by setting the properties of the class. While this may not seem like much at first, you will appreciate it when Visual Studio displays the properties and values that are commonly used with IntelliSense. Once the connection string was made, we used it to create a new Connection object. We chose to use a variable called objCon to point to this object using this code: objCon = new Data.OleDb.OleDbConnection(objBuilder.ConnectionString) Next, we built our SQL Insert statement using the data passed into the BugData parameter, as shown here: strInsert = " Insert Into ReportedBugs " strInsert += " (Tester, AppName, Build, DateReported, Description) " strInsert += " Values( " + BugData + " ) " To issue the SQL command, we created a Command object from the ADO Command class and set the Connection, CommandType, and CommandText properties as needed: objComm = new Data.OleDb.OleDbCommand() objComm.Connection = objCon objComm.CommandType = Data.CommandType.Text objComm.CommandText = strInsert
Making Barcode In None
Using Barcode creator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Code 128 Code Set A Generation In None
Using Barcode drawer for Font Control to generate, create Code 128 Code Set B image in Font applications.
www.OnBarcode.com
CHAPTER 9 CREATING WEB-BASED TESTWARE
EAN / UCC - 13 Maker In None
Using Barcode maker for Font Control to generate, create GS1 - 13 image in Font applications.
www.OnBarcode.com
GS1-128 Drawer In None
Using Barcode creator for Font Control to generate, create UCC.EAN - 128 image in Font applications.
www.OnBarcode.com
Note You may notice that we are using a Try-Catch block around the code that opens the connection
Print Universal Product Code Version A In None
Using Barcode generator for Font Control to generate, create GS1 - 12 image in Font applications.
www.OnBarcode.com
GTIN - 12 Generator In None
Using Barcode creator for Font Control to generate, create Universal Product Code version E image in Font applications.
www.OnBarcode.com
and executes the query. If there is an error, using the Catch block provides an error message to help with troubleshooting. One common issue happens when the application does not find the database file. We have chosen to place the file on the root of the C:\ drive to make this less likely to happen; but when testing real applications, this is something to watch for.
Decode PDF417 In .NET Framework
Using Barcode reader for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
PDF-417 2d Barcode Creator In None
Using Barcode generator for Online Control to generate, create PDF 417 image in Online applications.
www.OnBarcode.com
When the ExecuteNonQuery() method is called, the Insert statement is sent to Access. After it completes, we close the connection and redirect the user back to the default web page using ASP.NET s Response.Redirect() method. This example only allows the user to submit bug reports, but more features could be added later (such as the ability to edit and remove a bug report). To allow changes like these, you would use this same code, but modify the statements to delete and update the bug reports by executing those types of SQL statements.
Make PDF-417 2d Barcode In .NET Framework
Using Barcode maker for Reporting Service Control to generate, create PDF417 image in Reporting Service applications.
www.OnBarcode.com
Data Matrix 2d Barcode Maker In Java
Using Barcode generation for Java Control to generate, create Data Matrix ECC200 image in Java applications.
www.OnBarcode.com
Viewing Data from a Database
Code 39 Creator In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Code 3/9 image in .NET framework applications.
www.OnBarcode.com
Recognizing QR In C#.NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Displaying the contents of the ReportedBugs table is another example of where this code can be reused. To do this, you need to execute a SQL Select statement indicating which columns and rows you would want returned. Once you retrieve data from your database to your web server, you need to store these results in memory, at least temporarily. In ADO.NET, you have two choices: the DataReader and the DataSet. Both of these classes are used to make an object that holds the results coming back from a SQL Select statement, but the DataSet has a lot more features while the DataReader takes up less memory. Additionally, the DataSet can be added easily to the web server s cache, where it will be used repeatedly by many web page requests. The DataReader, on the other hand, cannot be cached directly. Oh, you can build an array, pour the contents of the DataReader into the array, and cache the array yourself, but this seems like a lot of extra work when the DataSet class is already available. A cached DataSet is often used on websites that have a lot of traffic. To understand why this is, consider that, unlike a Windows application, the objects created on a web page are destroyed and re-created each time the page is refreshed. As you might imagine, this creates a lot of extra work on the web server. To counter this, web developers will often hold a copy of data in local memory of the web server. These caches of data are useful because they are not destroyed for each page request, but, instead, are reused until the developer thinks that new or updated data is required. However, where it gets tricky is deciding how often the cached data needs refreshing. Some items, like a list of all the states a company ships to, is seldom updated and is a prime candidate for caching. Some data, like an inventory list, must be up to date every time the user needs to know how many items are still in stock. If this data was cached and only updated every 30 minutes, you can image that at some point someone would think an item was in stock when it was actually sold out almost a half hour ago. Although caching is a powerful feature, if you want to simply issue a SQL Select statement and display the result to a web page, it s hard the fault the use of a DataReader. It has low memory requirements and is easy to use.
Recognizing PDF-417 2d Barcode In Visual C#.NET
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Drawing Data Matrix ECC200 In Java
Using Barcode creation for BIRT reports Control to generate, create DataMatrix image in BIRT reports applications.
www.OnBarcode.com
Making PDF 417 In None
Using Barcode drawer for Software Control to generate, create PDF-417 2d barcode image in Software applications.
www.OnBarcode.com
Barcode Printer In Java
Using Barcode creation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Generate UPC - 13 In Objective-C
Using Barcode maker for iPhone Control to generate, create EAN / UCC - 13 image in iPhone applications.
www.OnBarcode.com
Decoding PDF-417 2d Barcode In VS .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.