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How to setup a nested form in Ruby on Rails

The first to thing to have: a model that contains a has_many relation with another model. class Project < ApplicationRecord has_many :todos end class Todo < ApplicationRecord belongs_to :project end In ProjectsController: class ProjectsController < ApplicationController d...

Blocking on async code can cause deadlocks

It is a bad practice to block on async calls as it can cause deadlocks in environments that have a synchronization context. The best practice is to use async/await "all the way down." For example, the following Windows Forms code causes a deadlock: private async Task<bool> TryThis()...

Save to disk with SaveFileDialog

//Using File.WriteAllBytes using (ExcelPackage excelPackage = new ExcelPackage()) { //create a new Worksheet ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add("Sheet 1"); //add some text to cell A1 worksheet.Cells["A1"].Value = "My fourt...

JSP out implicit object - simply displaying date and time.

<html> <body> <% out.print("Today is:"+java.util.Calendar.getInstance().getTime()); %> </body> </html>

Intro to Data Structures

A data structure is a way of organizing and storing information. Let a "Hello, World!" string be the information that we need to organize and store in byte-addressable memory. Each ASCII character requires 7 bits of storage. Most systems reserve 8 bits (1 byte) for each character, so eac...

Interface details

Ifconfig List all the interfaces available on the machine $ ifconfig -a List the details of a specific interface Syntax: $ ifconfig <interface> Example: $ ifconfig eth0 eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx inet addr:x.x.x.x Bcast:x.x.x.x Mask:x.x.x.x ...

Local DNS resolution

File: /etc/hosts contains a list of hosts that are to be resolved locally(not by DNS) Sample contents of the file: 127.0.0.1 your-node-name.your-domain.com localhost.localdomain localhost XXX.XXX.XXX.XXX node-name The file format for the hosts file is specified by RFC 952

Configure DNS servers for domain name resolution

File: /etc/resolv.conf contains a list of DNS servers for domain name resolution Sample contents of the file: nameserver 8.8.8.8 # IP address of the primary name server nameserver 8.8.4.4 # IP address of the secondary name server In case internal DNS server you can validate if this server reso...

Decompile Database

This should always be your initial fix. A good policy is to decompile the database before each release. Create a decompile shortcut. This loads the database with a "/decompile" switch. Right Click your Database File. Select Copy Right Click in the explorer window and select &quot...

Test Computer Memory

If your crashes are random or sporadic, then do this step. If your crashes occur every single time you run the database, then this step won't fix the issue (although bad memory may be the reason why the corruption occurred in the first place). Use a memory tester that boots outside the operating sy...

Remove "OLE Object" fields

If you have images or other data stored in Access itself as OLE Objects, then you should find a better approach. When the OLE data is stored, it is stored according to the software (and version of software) on the computer storing it. When another computer goes to display that OLE Object data on the...

Rebuild the entire database

This is a lot of work, so do this as a last resort after exhausting all other options. You only need to do this if the problem is occurring for different users, on different machines. If it isn't occurring for all users, then most likely it is not a corrupt database container. Similar to the steps...

Installation of Pyglet

Install Python, go into the command line and type: Python 2: pip install pyglet Python 3: pip3 install pyglet

The C++ compilation process

When you develop a C++ program, the next step is to compile the program before running it. The compilation is the process which converts the program written in human readable language like C, C++ etc into a machine code, directly understood by the Central Processing Unit. For example, if you have a...

See and manipulate routes

Manipulate the IP routing table using route Display routing table $ route # Displays list or routes and also resolves host names $ route -n # Displays list of routes without resolving host names for faster results Add/Delete route OptionDescriptionadd or delAdd or delete a route-host x.x.x.xA...

Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM

Appearance: "Paamayim Nekudotayim" means "double colon" in Hebrew; thus this error refers to the inappropriate use of the double colon operator (::). The error is typically caused by an attempt to call a static method that is, in fact, not static. Possible Solution: $classname...

Getting Started

Detailed instructions on getting amazon-cloudformation set up or installed. Amazon cloud formation templates can be launched in three ways. AWS Console. AWS CLI. AWS SDK available in Java, Ruby etc.. AWS CLI is one of the most intuitive CLI available. The commands are simple to ...

Playing Sound in Pyglet

sound = pyglet.media.load(sound.wav) sound.play()

Static bootstrapping with factory classes

We can statically bootstrap an application by taking the plain ES5 Javascript output of the generated factory classes. Then we can use that output to bootstrap the application: import { platformBrowser } from '@angular/platform-browser'; import { AppModuleNgFactory } from './main.ngfactory'; //...

forms.html

<!DOCTYPE html> <html> <head> <base target="_top"> <script> setInterval( function () { document.getElementById('messages').innerHTML = 'Event Timer Fetching'; google.script.run .withSuccessHandler(onS...

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