Microsoft NET Framework in Visual Studio .NET

Drawing EAN-13 Supplement 5 in Visual Studio .NET Microsoft NET Framework

Microsoft NET Framework
Recognizing EAN13 In .NET
Using Barcode Control SDK for Visual Studio .NET Control to generate, create, read, scan barcode image in VS .NET applications.
Painting EAN 13 In Visual Studio .NET
Using Barcode creator for Visual Studio .NET Control to generate, create EAN13 image in .NET applications.
The NpgsqlParameterCollection Class
Reading EAN13 In Visual Studio .NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET applications.
Making Barcode In .NET Framework
Using Barcode creator for VS .NET Control to generate, create bar code image in .NET applications.
All of the SQL commands used so far have been built before being used in the NpgsqlCommand object This does not provide much flexibility If you need to run a command again using different values (such as query using different WHERE parameters), you would have to rewrite the entire SQL command and place it in the NpgsqlCommand object This can become tedious in larger applications To help solve this problem, the Npgsql library contains the NpgsqlParametersCollection class, which holds parameters that are used as placeholders in NpgsqlCommand objects These parameters can easily be changed while using the same NpgsqlCommand object This feature allows you to quickly and easily change SQL command values within your application The Parameters property of the NpgsqlCommand defines an NpgsqlParameterCollection object that is used to contain the parameters used in the SQL command If this is starting to sound confusing, sometimes it can be The best way to demonstrate this concept is to use an example First, a parameter must be defined in an NpgsqlCommand CommandText object A colon is used to identify a parameter in the CommandText object:
Reading Barcode In Visual Studio .NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
Printing GTIN - 13 In Visual C#
Using Barcode printer for .NET framework Control to generate, create EAN 13 image in Visual Studio .NET applications.
commCommandText = "SELECT * from auctionbidder where bidderkey = :bidder";
European Article Number 13 Drawer In .NET
Using Barcode printer for ASP.NET Control to generate, create EAN-13 Supplement 5 image in ASP.NET applications.
European Article Number 13 Maker In Visual Basic .NET
Using Barcode drawer for .NET Control to generate, create EAN 13 image in .NET framework applications.
The :bidder identifier is a parameter placeholder that can be replaced with a value when the SQL command is executed The next step is to add the parameter to the NpgsqlParameterCollection object defined in the NpgsqlCommand object:
Drawing Barcode In Visual Studio .NET
Using Barcode generator for Visual Studio .NET Control to generate, create bar code image in VS .NET applications.
Encode Barcode In .NET
Using Barcode printer for Visual Studio .NET Control to generate, create barcode image in .NET applications.
commParametersAdd(new NpgsqlParameter("bidder", NpgsqlDbTypeInt32));
Draw 2D Barcode In .NET Framework
Using Barcode drawer for .NET framework Control to generate, create Matrix 2D Barcode image in VS .NET applications.
Generating Identcode In Visual Studio .NET
Using Barcode generator for VS .NET Control to generate, create Identcode image in VS .NET applications.
The Add()method adds a new NplgsqlParameter object to the NpgsqlParameterCollection object The parameter name and data type are defined in the constructor You can add as many parameters as necessary Each parameter added is referenced by its index value in the collection To assign a value to the parameter, reference the Value property of the appropriate indexed Parameters property:
Creating Bar Code In None
Using Barcode printer for Font Control to generate, create barcode image in Font applications.
UPC Code Creator In Java
Using Barcode generator for Android Control to generate, create UPC-A image in Android applications.
commParameters[0]Value = 100;
Encode EAN 128 In Java
Using Barcode encoder for Android Control to generate, create GS1 128 image in Android applications.
Bar Code Printer In Java
Using Barcode printer for BIRT Control to generate, create barcode image in BIRT reports applications.
The paramtestvb program is a more complicated example of using the parameter feature:
GS1-128 Printer In None
Using Barcode generator for Microsoft Word Control to generate, create GS1 128 image in Office Word applications.
Code 39 Extended Creation In VS .NET
Using Barcode printer for Reporting Service Control to generate, create ANSI/AIM Code 39 image in Reporting Service applications.
Imports System Imports SystemData Imports Npgsql Public Class ParamTest Public Shared Sub Main() Dim Dim Dim Dim Dim conn As NpgsqlConnection comm as NpgsqlCommand data as NpgsqlDataReader connstring as String comstring as String
Bar Code Generation In Visual Studio .NET
Using Barcode printer for Reporting Service Control to generate, create bar code image in Reporting Service applications.
Bar Code Printer In None
Using Barcode drawer for Online Control to generate, create bar code image in Online applications.
PostgreSQL 8 for Windows
Dim Dim Dim Dim Dim
bidder as String bidderval as Integer bidderkey as String lastname as String firstname as String
connstring = "Server=127001;Port=5432;SSL=True;User Id=earl;" connstring = connstring & "Password=auction;Database=test;" conn = New NpgsqlConnection(connstring) Try connOpen() Catch e as NpgsqlException ConsoleWriteLine("Problem opening session: {0}", eMessage) Exit Sub End Try comm = New NpgsqlCommand() commConnection = conn comstring = "Select * from auctionbidder where bidderkey = :bidder" commCommandtext = comstring commParametersAdd(new NpgsqlParameter("bidder", DbTypeInt32)) While(True) ConsoleWrite("Enter bidder: ") bidder = ConsoleReadLine() bidderval = ConvertToInt32(bidder) If (bidderval = 0) Exit While End If Try commParameters(0)Value = bidderval data = commExecuteReader() If (dataHasRows) While(dataRead()) bidderkey = dataGetInt32(0) lastname = dataGetString(1) firstname = dataGetString(2) ConsoleWriteLine("{0} - {1},{2}", bidderkey,lastname,firstname) End While Else ConsoleWriteLine(" No bidder found") End If Catch e2 as NpgsqlException ConsoleWriteLine("Problem: {0}", e2Message) Exit While End Try End While connClose() End Sub End Class
13:
Microsoft NET Framework
The first part of the paramtestvb program should look familiar A connection is established with the PostgreSQL server, and an NpgsqlCommand object is created, using a parameter placeholder in the query The parameter is defined using the Add() method, and set as an Int32 data type Next, a WHILE loop is started In the WHILE loop a value is retrieved from the user input, converted to an int32 data type, then assigned to the parameter Value property After the value is assigned, the ExecuteReader() method is executed and the result set is stored in the NpgsqlDataReader object The values are extracted using the Getxxx methods, and the record is displayed The output of the program should look something like this:
C:\>paramtest Enter bidder: 110 No bidder found Enter bidder: 100 100 - Blum,Rich Enter bidder: 103 103 - Blum,Jessica Enter bidder: 150 150 - Test,Ima Enter bidder: 0 C:\>
Copyright © OnBarcode.com . All rights reserved.