vb.net code 39 generator source code C05620245.fm Page 148 Tuesday, June 8, 2004 6:39 PM in .NET

Print Code 128 in .NET C05620245.fm Page 148 Tuesday, June 8, 2004 6:39 PM

C05620245.fm Page 148 Tuesday, June 8, 2004 6:39 PM
Paint Code 128 In .NET Framework
Using Barcode creator for ASP.NET Control to generate, create Code 128 Code Set A image in ASP.NET applications.
www.OnBarcode.com
Barcode Creation In VS .NET
Using Barcode creation for ASP.NET Control to generate, create bar code image in ASP.NET applications.
www.OnBarcode.com
Part II
USS Code 128 Maker In C#.NET
Using Barcode encoder for .NET Control to generate, create Code128 image in .NET applications.
www.OnBarcode.com
Code128 Generation In .NET Framework
Using Barcode creator for VS .NET Control to generate, create Code 128B image in Visual Studio .NET applications.
www.OnBarcode.com
Data Access
Code 128 Code Set A Drawer In VB.NET
Using Barcode generator for .NET framework Control to generate, create Code 128B image in .NET applications.
www.OnBarcode.com
USS Code 39 Creator In .NET
Using Barcode creator for ASP.NET Control to generate, create Code 39 Full ASCII image in ASP.NET applications.
www.OnBarcode.com
// Start a nonblocking execution IAsyncResult iar = cmd.BeginExecuteReader(); // Do something else in the meantime // Block the execution until done SqlDataReader reader = cmd.EndExecuteReader(iar); // Process data here ... Repeater1.DataSource = reader; Repeater1.DataBind();
GS1 - 12 Printer In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create Universal Product Code version A image in ASP.NET applications.
www.OnBarcode.com
PDF417 Generation In VS .NET
Using Barcode printer for ASP.NET Control to generate, create PDF 417 image in ASP.NET applications.
www.OnBarcode.com
The BeginExecuteReader function returns an IAsyncResult object that you use later to complete the call. Note that EndExecuteReader is called to finish up the operation; it blocks execution until the ongoing command terminates. Note that to enable asynchronous operations, you must set the new Async attribute to true in the connection string. The EndExecuteReader function syncs up the command with the rest of the application, blocking the code whenever the results of the command are not ready. You can avoid this blocking schema by periodically polling for completion. The following code illustrates the polling option with a nonquery statement.
Print QR Code JIS X 0510 In VS .NET
Using Barcode drawer for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
www.OnBarcode.com
EAN / UCC - 13 Generation In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create EAN-13 image in ASP.NET applications.
www.OnBarcode.com
// Executes a nonquery statement IAsyncResult ar = cmd.BeginExecuteNonQuery(); // Do some work in the meantime do { // Poll from time to time while(!ar.IsCompleted) { done = true; } while (!done) // Sync up cmd.EndExecuteNonQuery(ar); }
Bar Code Encoder In VS .NET
Using Barcode creator for ASP.NET Control to generate, create barcode image in ASP.NET applications.
www.OnBarcode.com
Ames Code Printer In VS .NET
Using Barcode creation for ASP.NET Control to generate, create 2 of 7 Code image in ASP.NET applications.
www.OnBarcode.com
Note that if ar.IsCompleted returns true, the EndExecuteNonQuery will not block the application. You can also pass a callback function to a BeginExecuteXXX method and any information that constitutes the state of the particular call. The state is any information you want to pass to the callback function. In this case, we just pass a reference to the command object:
Data Matrix 2d Barcode Scanner In Visual Basic .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Generating Bar Code In Visual Studio .NET
Using Barcode generation for Reporting Service Control to generate, create barcode image in Reporting Service applications.
www.OnBarcode.com
C05620245.fm Page 149 Tuesday, June 8, 2004 6:39 PM
Bar Code Printer In Objective-C
Using Barcode encoder for iPhone Control to generate, create barcode image in iPhone applications.
www.OnBarcode.com
GS1 128 Generator In None
Using Barcode maker for Software Control to generate, create EAN 128 image in Software applications.
www.OnBarcode.com
5
Bar Code Creator In C#.NET
Using Barcode maker for .NET framework Control to generate, create barcode image in .NET applications.
www.OnBarcode.com
Code-128 Printer In Objective-C
Using Barcode generation for iPad Control to generate, create Code 128 image in iPad applications.
www.OnBarcode.com
What s New in Data Access
Drawing Code 3 Of 9 In None
Using Barcode creation for Font Control to generate, create Code 39 Extended image in Font applications.
www.OnBarcode.com
Decode Code 39 Extended In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
// Begin executing the command IAsyncResult ar = cmd.BeginExecuteReader( new AsyncCallback(PopulateRepeaterCallback), cmd);
After initiating the asynchronous operation, you can forget about it and do any other work. If there s a place in your code that you can t move away from without the results of the query, place a synchronizer there so your code will automatically stop until the other thread terminates and invokes the callback:
// Optionally wait to sync ar.AsyncWaitHandle.WaitOne();
The specified callback function is invoked at the end of the operation. The callback must have the following layout:
public void PopulateRepeaterCallback(IAsyncResult ar) { // Retrieve the context of the call SqlCommand cmd = (SqlCommand) ar.AsyncState; // Finalize the async operation SqlDataReader reader = cmd.EndExecuteReader(ar); }
The context of the call you specified as the second argument to BeginExecuteReader is packed in the AsyncState property of the IAsyncResult object.
Important The primary thread doesn t execute the callback code. The callback code runs under the control of the secondary thread spawned to accomplish the asynchronous operation. This poses a problem with the user interface of applications, especially Windows Forms applications. It s up to you to ensure that the UI is refreshed in the right thread.
Bulk Copy Operations
Bulk copy functionality provides a much faster way to transfer large amounts of data into a SQL Server table. You typically get much better performance using a specialized operation such as a bulk copy than using an INSERT statement. In SQL Server 7.0 and later, the BULK INSERT statement copies into a SQL Server table formatted data stored in an ASCII file. You can use this statement from
C05620245.fm Page 150 Tuesday, June 8, 2004 6:39 PM
Part II
Data Access
within any .NET Framework 1.1 application that uses an appropriate SqlCommand object. Note that this technique is completely unrelated to the bulk copy functionality provided by the SQL Server .NET data provider in ADO.NET 2.0. In other words, the SqlBulkCopy class of ADO.NET 2.0 is not exactly a bare wrapper around the T-SQL BULK INSERT statement. As you ll see in a moment, it is even more efficient than a plain call to the BULK INSERT statement.
The SqlBulkCopy Class
The SqlBulkCopy class represents a bulk copy operation to execute against a SQL Server database. Unlike the equivalent T-SQL statement, though, no formatted disk file is managed, either implicitly by the framework or explicitly by the programmer. Interestingly enough, you copy data to SQL Server from an ADO.NET data reader or a DataTable object. The programming interface of the SqlBulkCopy class consists of the properties listed in Table 5-2. Table 5-2 Properties of the SqlBulkCopy Class
Property BatchSize Description Specifies the number of rows in each batch of a bulk copy operation. The default is 0, which means that the copy occurs in a single step. Specifies the amount of time, in seconds, before a bulk copy operation times out. The default is 30 seconds. A collection object that defines the mapping between the data source and the destination table. Specifies the name of the destination SQL Server table. Specifies the number of rows to process before the SqlRowsCopied notification event is generated. The default is 0, which means that just one event is raised.
Copyright © OnBarcode.com . All rights reserved.