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A generic method allows you to specify parameters and return type by using a type. You define generic methods by using the same type parameter syntax that you use when creating generic classes (you can also specify constraints). For example, the generic Swap<T>. static void Swap<T>( ref T first, ref T second). The following examples show how to use the...
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So far you have used Visual Studio 2005 to create and run a basic Console application.. The Visual Studio 2005 programming environment also contains everything you'll need to create graphical Windows applications. You can design the form-based user interface of a Windows application interactively by using the Visual Designer. Visual Studio 2005 then generates the program statements to implement the...
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Inheriting from a class is a powerful mechanism, but the real power of inheritance comes from inheriting from an interface. An interface allows you to completely separate the name of a method from its implementation.. You can define an interface that includes this method, and specify that the collection class will allow only classes that implement this interface as its...
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As an example, you are going to create an application that allows a user to input and display details for members of the Middleshire Bell Ringers Association, an esteemed collection of the finest campanologists. Initially you will keep the application very simple, concentrating on laying out the form and making sure that it all works. (You can see the completed...
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changes in the Design View. Any code that you need to write yourself should be placed in the Form1.cs file.. In the Solution Explorer, you should notice another source file called Program.cs. If you double-click this file the following code appears in the Code and Text Editor window:. In the following exercise, you'll learn how to add code that runs...
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To do this, you declare the get or set keyword, or both, but replace the body of the get or set accessor with a semicolon. In the following exercise, you will use some predefined properties of the TextBox controls and the Form class to create a simple application that continually displays the size of its main window, even when the...
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C# allows you to declare your own version of the increment. Here is the increment operator for the Hour struct:. The result of a postfix expression is the value of the operand before the expression takes place. The result of a prefix expression is the return value of the operator. This equivalence means that the return type of the increment...
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This neither-or-both rule also applies to the <. The GetHashCode method is used by other classes in the .NET. All this method needs to do is return a distinguishing integer value (don't return the same integer from the GetHashCode method of all your objects though as this will reduce the effectiveness of the hashing. You have seen how to use...
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In the previous section, you saw how to declare a delegate type, call a delegate, and create delegate instances. For example, in the automated factory scenario, it could be vital to be able to invoke the stopMachinery delegate and halt the equipment if a machine overheats. In the .NET Framework, events allow you to define and trap. Many classes in...
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If you are familiar with Microsoft Visual Basic, Microsoft Foundation Classes (MFC), or any of the other tools available for building GUI applications for Windows, you are aware that Windows uses an event-driven model to determine when to execute code. This is what you will do in the final exercise in this chapter.. Handle the Click event for the Clear...
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Now that you can control access to your application, you can turn your attention to querying and maintaining data. You will useWeb Server Data controls to connect to the database, query data, and maintain the data, in a manner similar to that used by the Windows Forms application you built in Chapter 24, “Working with Data Binding and DataSets.”. In...
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The SqlDataSource control has a property called DataSourceMode which you can set to DataSet (the default) or. A DataSet contains a copy of the data it fetches. The SQL SELECT statement will also be executed again if you simply refresh the view of the Web form in the browser. In this way, you are always presented with a copy of...
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The using statement is designed to solve all these problems.. The using Statement. The using statement provides a clean mechanism for controlling the lifetimes of resources. You can create an object, and this object will be destroyed when the using statement block finishes.. Do not confuse the using statement shown in this section with the using directive that brings a...
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If you create an interface or an abstract class, you are knowingly writing something that will be inherited from in the future. You can never derive from a struct.. You can also use the sealed keyword to declare that an individual method is sealed. You can only seal an override method (you declare the method as sealed. override).You can think...
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The factory contains a large number of different machines, each performing distinct tasks in the production of the articles manufactured by the factory—shaping and folding metal sheets, welding sheets together, painting sheets, and so on. You can think of the .NET Framework as a set of APIs, as it provides methods allowing you to control the .NET common language runtime...
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Generic classes and methods accept type parameters, which specify the type of objects that they operate on. Queue<Circle>. myQueue = new Queue<Circle>();. The use of the type parameter between the angle brackets, <Circle>, when declaring the myQueue variable.. The type parameter specifies the type of objects accepted by the queue. If you examine the description of the generic Queue class...
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The Life and Times of an Object. First, let's recap what happens when you create and destroy an object.. You create an object like this:. You have no control over this phase of an object's creation. Second, the new operation has to convert the raw memory into an object. it has to initialize the object.. You can control this phase...
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In the following exercise, you will familiarize yourself with a small hierarchy of. The framework is a Microsoft Windows application that simulates reading a C# source file and. A displaying visitor class that displays the source file in a rich text box.. A printing visitor class that converts tabs to spaces and aligns braces correctly.. A spelling visitor class that...
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You'll learn the meaning of most of the keywords as you proceed through this book. The keywords are listed in the following table.. In the Visual Studio 2005 Code and Text Editor window, keywords are colored blue when you type them.. These two chunks of memory are traditionally called the stack and the heap. The stack and the heap serve...
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Implementing an Enumerator by Using an Iterator. According to the C# 2.0 specification, an iterator is a block of code that yields an ordered sequence of values. Additionally, an iterator is not actually a member of an enumerable class. In other words, an iterator is just a description of the enumeration sequence that the C# compiler can use for creating...