State in .NET

Print QR Code in .NET State

State
QR Code Generator In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
www.OnBarcode.com
ANSI/AIM Code 39 Generation In .NET
Using Barcode generator for ASP.NET Control to generate, create Code 39 Full ASCII image in ASP.NET applications.
www.OnBarcode.com
|
Create PDF 417 In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create PDF 417 image in ASP.NET applications.
www.OnBarcode.com
QR Code Creation In VS .NET
Using Barcode printer for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
www.OnBarcode.com
The page is very different, as shown in Figure 7-8.
Encoding DataMatrix In VS .NET
Using Barcode drawer for ASP.NET Control to generate, create DataMatrix image in ASP.NET applications.
www.OnBarcode.com
Creating Barcode In .NET
Using Barcode drawer for ASP.NET Control to generate, create Barcode image in ASP.NET applications.
www.OnBarcode.com
The TextBox still shows the current value. As mentioned in the note above, simple controls such as TextBox ignore the EnableViewState property and always preserve view state. However, the Label and GridView controls do respect that property. Since they are only populated the first time the page is loaded, they no longer display the current data after the page is posted back to the server. The Label reverts to its default Text property, and the GridView is not even rendered to the browser if there is no data bound to it. In addition to preserving the values of controls, View state is very handy for something else; you can programmatically stash your own stuff in a data structure known as the state bag, using the ViewState keyword. The state bag stores data as attribute/ value pairs in a dictionary. The attribute is a string, which is the name of the object stored as the value. The types of objects that can be stored efficiently are the primitive data types, including integers, strings, bytes, and Booleans. You can also store arrays of primitive types. Complex types, such as DataSets and custom objects can be stored as well, but performance will suffer. The next example demonstrates stashing values in the state bag and then retrieving them. In this example, a counter keeps track of the number of times a button on a page has been clicked. As long as the page is current, the count will be correct. If you move to another page and then return to this page, the count will start over. Create a new web site called StateBag. On the Default page, drag a Label, called lblCounter, and two buttons. Set the Text property of one button to Increment Counter, and the Text property of the other button to Navigate.
UCC-128 Drawer In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create EAN 128 image in ASP.NET applications.
www.OnBarcode.com
2 Of 5 Standard Printer In .NET
Using Barcode printer for ASP.NET Control to generate, create Code 2 of 5 image in ASP.NET applications.
www.OnBarcode.com
|
QR Maker In None
Using Barcode generation for Font Control to generate, create QR-Code image in Font applications.
www.OnBarcode.com
Create QR Code JIS X 0510 In None
Using Barcode creator for Microsoft Excel Control to generate, create QR-Code image in Office Excel applications.
www.OnBarcode.com
7: State and Life Cycle
Barcode Generation In Java
Using Barcode creation for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
PDF417 Creator In VB.NET
Using Barcode generation for .NET Control to generate, create PDF-417 2d barcode image in .NET applications.
www.OnBarcode.com
VB CHEAT SHEET
Generating PDF 417 In None
Using Barcode maker for Software Control to generate, create PDF-417 2d barcode image in Software applications.
www.OnBarcode.com
Scanning EAN13 In Visual Basic .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Arrays and Dictionaries
PDF-417 2d Barcode Printer In None
Using Barcode generation for Font Control to generate, create PDF417 image in Font applications.
www.OnBarcode.com
UCC - 12 Generator In None
Using Barcode drawer for Font Control to generate, create UPC A image in Font applications.
www.OnBarcode.com
You ve seen variables in previous chapters, and you ve seen collections, like the collection of ListItems in a RadioButtonList. An array is simply another type of collection, in which you can store a bunch of objects in a single variable, provided they re all of the same type. You declare an array similar to the way you would create a variable:
Reading Barcode In VS .NET
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
www.OnBarcode.com
Generate DataBar In Visual Studio .NET
Using Barcode maker for Visual Studio .NET Control to generate, create GS1 DataBar Stacked image in .NET framework applications.
www.OnBarcode.com
Dim myArray(5) As Integer
EAN / UCC - 13 Generation In Java
Using Barcode maker for Java Control to generate, create EAN13 image in Java applications.
www.OnBarcode.com
Paint ANSI/AIM Code 128 In Objective-C
Using Barcode creation for iPhone Control to generate, create Code 128A image in iPhone applications.
www.OnBarcode.com
This code creates an array called myArray, which can hold integers. Specifically, the (5) states that the array can hold six integers. Why not five as the code suggests Because just as with controls, array indexes begin at zero. To access the third integer in the array, you d just use this syntax:
myArray(2)
Use curly braces if you want to initialize the array when you create it:
Dim myArray( ) As Integer = {42, 36, 128, 53, 7, 85}
Notice you don t have to specify the length of the array; the compiler will automatically set it to a length of six. Arrays are particularly useful with ForEach loops, like this:
ForEach i In myArray i = i + 1 Next i
That little loop increments each element in the array by 1, and you don t need to know what values are in the array, or how many there are. One drawback to arrays is that if you want to retrieve a value from an array, you either have to know the index of the value you want, or else loop through the array until you find it. The dictionary is a specific kind of array (also known as a Hashtable) that solves this problem by associating each value with a key, instead of an index. For example, you could have a dictionary of U.S. states, using their abbreviations as the key values. Then, to retrieve a state s name, you d just have to know the abbreviation (the key). The following code snippet creates and partially populates a Hashtable to hold the states:
Dim States as New Hashtable( ) States.Add("CA", "California") States.Add("MA", "Massachusetts") States.Add("PA", "Pennsylvania")
To retrieve the name of the dictionary entry with the key value of MA, you would use the following code:
Dim strStateName as string = States("MA").ToString( )
In the case of the state bag, the attribute names are the keys, and the values of those attributes are stored as the value part of each dictionary pair.
Copyright © OnBarcode.com . All rights reserved.