asp.net barcode generator Multiple Items per Key in Font

Maker Data Matrix 2d barcode in Font Multiple Items per Key

Multiple Items per Key
Make Data Matrix In None
Using Barcode generation for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
Making DataMatrix In None
Using Barcode encoder for Font Control to generate, create Data Matrix 2d barcode image in Font applications.
www.OnBarcode.com
The QMap and QHash classes store one item for each key. When you want to have a list of items for each key, you can use QMultiMap and QMultiHash. These classes relate to each other just as QMap relates to QHash key order is preserved in the map; hashes are quicker but order the keys arbitrarily. This section discusses the QMultiMap class, but all that I say also applies to the QMultiHash class. The QMultiMap class does not have a [] operator; instead, the insert method is used for adding values and the method values for accessing the inserted items. Because the QMultiMap can contain multiple elements for a key, the values method returns a QList with the items associated with the given key. Before requesting a list, it is possible to see how many items are associated to a given key using the count method.
Painting USS Code 128 In None
Using Barcode creation for Font Control to generate, create Code 128B image in Font applications.
www.OnBarcode.com
Code-39 Generation In None
Using Barcode generator for Font Control to generate, create USS Code 39 image in Font applications.
www.OnBarcode.com
CHAPTER 1 THE QT WAY OF C++
Make QR Code JIS X 0510 In None
Using Barcode printer for Font Control to generate, create QR Code JIS X 0510 image in Font applications.
www.OnBarcode.com
UPC - 13 Printer In None
Using Barcode encoder for Font Control to generate, create EAN 13 image in Font applications.
www.OnBarcode.com
Note The multicollection QMultiMap and QMultiHash classes are just wrappers of the QMap and QHash
Making UCC.EAN - 128 In None
Using Barcode creator for Font Control to generate, create EAN128 image in Font applications.
www.OnBarcode.com
Code11 Maker In None
Using Barcode generator for Font Control to generate, create USD - 8 image in Font applications.
www.OnBarcode.com
classes. The QMap and QHash classes can be used as multicollections by using the insertMulti method, but it is easy to overwrite a list of items by accident by using the [] operator or insert method. Using the multicollections detects any such mistakes at compile-time and reduces the risk of hard-to-find bugs.
Printing ECC200 In Java
Using Barcode maker for Android Control to generate, create DataMatrix image in Android applications.
www.OnBarcode.com
Data Matrix Creator In Visual C#.NET
Using Barcode maker for .NET framework Control to generate, create Data Matrix 2d barcode image in .NET applications.
www.OnBarcode.com
Listing 1-26 shows how a QMultiMap is created and populated. This code does not contain any surprises. However, the relationship of QMultiMap with QMap shows that if you have a look at the list returned from the keys method, foo appears twice. The best way to find all the unique keys is to add all keys to a QSet and then iterate over it. Listing 1-27 shows how to first find all keys and then iterate over them, showing all items for each key. Listing 1-26. Creating and populating a QMultiMap QMultiMap<QString, int> multi; multi.insert( "foo", 10 ); multi.insert( "foo", 20 ); multi.insert( "bar", 30 ); Listing 1-27. Finding the unique keys and then iterating over each key and its associated items QSet<QString> keys = QSet<QString>::fromList(multi.keys());
Make ECC200 In Objective-C
Using Barcode encoder for iPad Control to generate, create Data Matrix image in iPad applications.
www.OnBarcode.com
2D Generation In C#.NET
Using Barcode printer for .NET Control to generate, create Matrix Barcode image in VS .NET applications.
www.OnBarcode.com
foreach( QString key, keys ) foreach( int value, multi.values(key) ) qDebug() << key << ": " << value; There is a quicker way to find all the items in a QMultiMap: use an iterator. A QMultiMap:: iterator has the member functions key and value, which are used to get the information that it contains. Iterators can also be used to find all the items for a given key in a highly efficient way. Using the find method, you can get an iterator that points to the first item belonging to a given key. As the keys are sorted, you can reach all items belonging to a given key by iterating until the iterator from find reaches the end of the QMultiMap or another key (Listing 1-28 shows an example). The iterator approach also avoids having to build a list with all the items belonging to the key, which is what happens when you use the values method saving both memory and time. Listing 1-28. Finding the items for a given key using an iterator QMultiMap<QString, int>::ConstIterator ii = multi.find( "foo" ); while( ii != multi.end() && ii.key() == "foo" ) { qDebug() << ii.value(); ++ii; }
2D Drawer In Java
Using Barcode generation for Java Control to generate, create 2D Barcode image in Java applications.
www.OnBarcode.com
Encode Barcode In .NET Framework
Using Barcode printer for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
CHAPTER 1 THE QT WAY OF C++
Code 128A Drawer In Java
Using Barcode printer for Android Control to generate, create Code128 image in Android applications.
www.OnBarcode.com
Reading GS1 - 12 In VS .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
In the start of this section, I said that all the information also applies to the QMultiHash class. Listing 1-29 shows this by performing the same task as in Listing 1-26, Listing 1-27, and Listing 1-28. The highlighted lines contain the changes needed only changes of which class to use. The only possible difference in outcome is that the keys are returned in an arbitrary order. Notice that this does not mean that the find and iterate method fails the keys appear in an arbitrary order, but are still in order. Listing 1-29. Finding the items for a given key using an iterator QMultiHash<QString, int> multi; multi.insert( "foo", 10 ); multi.insert( "foo", 20 ); multi.insert( "bar", 30 ); QSet<QString> keys = QSet<QString>::fromList(multi.keys());
Read DataMatrix In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Making QR In None
Using Barcode creator for Online Control to generate, create QR image in Online applications.
www.OnBarcode.com
foreach( QString key, keys ) foreach( int value, multi.values(key) ) qDebug() << key << ": " << value; QMultiHash<QString, int>::ConstIterator ii = multi.find( "foo" ); while( ii != multi.end() && ii.key() == "foo" ) { qDebug() << ii.value(); ++ii; }
Barcode Generator In Visual Studio .NET
Using Barcode maker for ASP.NET Control to generate, create Barcode image in ASP.NET applications.
www.OnBarcode.com
Barcode Scanner In Java
Using Barcode Control SDK for BIRT reports Control to generate, create, read, scan barcode image in Eclipse BIRT applications.
www.OnBarcode.com
Summary
Qt has a naming scheme that is recommended because it makes it easier to guess names of classes and methods. All elements use CamelCasing; that is, each new word starts with a capital letter, like this: ThisIsAnExample. Class names start with an uppercase letter, Qt classes are prefixed with a Q. This is an example of a Qt class: QMessageBox, and this is another class: MyClass. A class prefixed by a Q and a set of lowercase letters is a third-party Qt class; for example: QjColorPicker. When using a Qt class, make sure to include the header file with the same name as the class (this is case sensitive on most platforms) without any file extension (for example, the class QMessageBox is included by #include <QMessageBox>). Method names start with lowercase letters (for example, thisIsAMethod). Getter and setter methods are named foo and setFoo, respectively. If there is a signal that reflects a change in foo, it is usually called fooChanged. In the example here, foo is called a property. Regarding signals and slots: setters are natural candidates for slots and also a good place for emitting signals concerning changes. If you emit such a signal, make sure to check that the setter receives a new value, not the same value. Doing so avoids infinite recursion loops.
Copyright © OnBarcode.com . All rights reserved.