Tutorial by Examples: o

textBox.KeyPress += (sender, e) => e.Handled = !char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar); This will only permit the use of digits and control characters in the TextBox, other combinations are possible using the same approach of setting the Handle property to true to block ...

textBox.SelectionStart = textBox.TextLength; textBox.ScrollToCaret(); Applying the same principle, SelectionStart can be set to 0 to scroll to the top or to a specific number to go to a specific character.

A StringBuilder represents a series of characters, which unlike a normal string, are mutable. Often times there is a need to modify strings that we've already made, but the standard string object is not mutable. This means that each time a string is modified, a new string object needs to be created,...

You can configure the database settings in config/connections.js. Here's an example: postgresql: { database: 'databaseName', host: 'localhost', user: 'root', password: '', port: 5432, poolSize: 10, ssl: false }; Alternatively, you can supply the connection information in U...

Short circuiting is a functionality that skips evaluating parts of a (if/while/...) condition when able. In case of a logical operation on two operands, the first operand is evaluated (to true or false) and if there is a verdict (i.e first operand is false when using &&, first operand is tr...

OSX Implement the contract of the role-specific protocol (NSAccessibilityButton, NSAccessibilityImage, NSAccessibilityGroup, etc) within the NSAccessibility protocol that best matches the behavior of the GUI element being rendered. Linux / BSD For GNOME applications, the GNOME Accessibility Impl...

Lazy loading is enabled by default. Lazy loading is achieved by creating derived proxy classes and overriding virtual navigation proeprties. Lazy loading occurs when property is accessed for the first time. int companyId = ...; Company company = context.Companies .First(m => m.Id == compan...

Eager loading lets you load all your needed entities at once. If you prefer to get all your entities to work on in one database call, then Eager loading is the way to go. It also lets you load multiple levels. You have two options to load related entities, you can choose either strongly typed or st...

After turning Lazy loading off you can lazily load entities by explicitly calling Load method for entries. Reference is used to load single navigation properties, whereas Collection is used to get collections. Company company = context.Companies.FirstOrDefault(); // Load founder context.Entry(com...

The most common way is to apply the extension via Config. Example: # File: mysite/_config/config.yml Member: extensions: - MyMemberExtension The extensions config variable is of type "array", so you can add multiple extensions like this: # File: mysite/_config/config.yml Mem...

Some procedures have optional arguments. Optional arguments always come after required arguments, but the procedure can be called without them. For example, if the function, ProcedureName were to have two required arguments (argument1, argument2), and one optional argument, optArgument3, it could b...

library(gpuR) # gpuMatrix objects X <- gpuMatrix(rnorm(100), 10, 10) Y <- gpuMatrix(rnorm(100), 10, 10) # transfer data to GPU when operation called # automatically copied back to CPU Z <- X %*% Y

library(gpuR) # vclMatrix objects X <- vclMatrix(rnorm(100), 10, 10) Y <- vclMatrix(rnorm(100), 10, 10) # data always on GPU # no data transfer Z <- X %*% Y

From MSDN Use the CInt function to provide conversions from any other data type to an Integer subtype. For example, CInt forces integer arithmetic when currency, single-precision, or double-precision arithmetic would normally occur. Assuming that you have 1 button and 2 textbox. If you type...

TRACE and DEBUG log levels are there to be able to convey high detail about the operation of the given code at runtime. Setting the log level above these is usually recommended, however some care must be taken for these statements to not affect performance even when seemingly "turned off"....

In most cases, it is illegal to access an object of one type as though it were a different type (disregarding cv-qualifiers). Example: float x = 42; int y = reinterpret_cast<int&>(x); The result is undefined behavior. There are some exceptions to this strict aliasing rule: An obj...

This example will call the windows calculator. It's important to notice that the exit code will vary accordingly to the program/script that is being called. package process.example; import java.io.IOException; public class App { public static void main(String[] args) { try { ...

The ProcessBuilder class makes it easy to send a command through the command line. All it requires is a List of Strings that make up the commands to be entered. You simply call the start() method on your ProcessBuilder instance to execute the command. If you have a program called Add.exe which take...

In general when making a call to the command line, the program will send the command and then continue its execution. However you may want to wait for the called program to finish before continuing your own execution (ex. The called program will write data to a file and your program needs that to a...

Launching external processes from Java using the raw java.lang.ProcessBuilder API directly can be a little cumbersome. The Apache Commons Exec library makes it a little easier. The ch.vorburger.exec library further extends upon Commons Exec to make it truly convenient: ManagedProcess proc = new ...