Category Archives: classes

Give a class default indexer properties in C#

An indexer property is a property that other code can use inside square brackets to access some value provided by the class, much as you can use the index of an array. Unlike an array, a class’s indexer need not … Continue reading

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Use a TextFieldParser to read fixed-width data in C#

This example uses a TextFieldParser object to load fixed-width data from a file that contains names and addresses. Each field has a fixed width. Some records also have ZIP+4 format ZIP codes (for example, 08109-2120) and the program should discard … Continue reading

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Use a TextFieldParser to read delimited data in C#

This example uses a TextFieldParser object to parse a data file that contains name and address data. The data contains fields delimited by commas and semi-colons. Some records also have ZIP+4 format ZIP codes (for example, 08109-2120) and the program … Continue reading

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Draw a scrolling family tree in C#

The example Draw a family tree in C# shows how to draw a family tree. Unfortunately if the tree is too big, you can’t make the form big enough to display it all. One solution would be to use smaller … Continue reading

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Add “extension properties” to classes in C#

Extension methods allow you to add new methods to existing classes even if you don’t have access to the classes’ source code. For example, the Randomize two-dimensional arrays in C# example shows how to add an extension method to two-dimensional … Continue reading

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Draw trees vertically or horizontally in C#

The example Handle generic TreeNode mouse events in C# shows how to build a generic node class that can draw trees with nodes that contain just about anything. In that example, each each node is centered over its subtree. This … Continue reading

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Override a parent class method in C#

One of the coolest features of object-oriented programming is virtual methods. If a parent class declares a method as virtual, a child class can provide a new implementation for the method. When the program calls the method for a child … Continue reading

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Make an initializing constructor for a child class in C#

An initializing constructor is a constructor that takes parameters to make it easy to initialize an object’s properties. This example shows how to reuse a class’s initializing constructor for a child class. The following Person class has an initializing constructor. … Continue reading

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Use the is operator in C#

The is operator lets you determine whether you can convert an object to a particular type. For example, suppose the Student class inherits from Person, and that student and person are objects from the obvious classes. Then, for example, the … Continue reading

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Compare a list priority queue to a heap priority queue in C#

My book Essential Algorithms: A Practical Approach to Computer Algorithms describes lots of other interesting data structures and algorithms, many just as interesting but less complicated than this one. For more information about queues, priority queues, trees and other algorithmic … Continue reading

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