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What does “Object reference not set to an instance of an object” mean? [duplicate]
...
The following code is a simple way of reproducing this:
static void Main(string[] args)
{
var exampleClass = new ExampleClass();
var returnedClass = exampleClass.ExampleMethod();
returnedClass.AnotherExampleMethod(); //NullReferenceException here.
}
class ExampleClass
{
public Ret...
SQL query to get all values a enum can have
...
The unnest call will return records of type myenum with a column name of "myenum". You might also want to cast the enum to text and specify a column name by adding something like. ::text AS my_column
– Justin Oh...
Read and write a String from text file
...cuments directory. The following code shows how to read and write a simple string. You can test it on a playground.
Swift 3.x - 5.x
let file = "file.txt" //this is the file. we will write to and read from it
let text = "some text" //just a text
if let dir = FileManager.default.urls(for: .documen...
How to display double quotes(") Symbol in a TextView?
...
In the strings.xml, you can simply escape special characters (eg double quotes) with a backslash :
"message \"quote string 1\" and \"quote string 2\" end message"
But in views xml (eg layout.xml), you have to use HTML character e...
How do I list all versions of a gem available at a remote site?
...re safe (if putting sth like that in a script or README) is to put it in a string so that we're sure we pass it 1-1, i.e. gem list '^rhc$' etc.
– mgol
Oct 2 '13 at 3:04
1
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How to create multiple directories from a single full path in C#?
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Create directories from complete filepath
private String EvaluatePath(String path){
try
{
String folder = Path.GetDirectoryName(path);
if (!Directory.Exists(folder))
{
// Try to create the directory.
DirectoryInfo di =...
Measuring code execution time
...rick on it to get the miliseconds out of picture. this way watch.Elapsed.ToString().Split('.')[0]
– Doruk
Sep 7 '16 at 7:50
3
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How to stop a PowerShell script on the first error?
...andatory=1)][scriptblock]$cmd,
[Parameter(Position=1,Mandatory=0)][string]$errorMessage = ("Error executing command {0}" -f $cmd)
)
& $cmd
if ($lastexitcode -ne 0) {
throw ("Exec: " + $errorMessage)
}
}
Try {
# Put all your stuff inside here!
# powershe...
Performing Breadth First Search recursively
...tion, but I suppose I could imagine some bizarre scenario where you're not allowed any heap space for some reason [some really bad custom memory manager? some bizarre runtime/OS issues?] while you still have access to the stack...)
Breadth-first traversal traditionally uses a queue, not a stack. T...
How do I return early from a rake task?
... an exit code of 1) you'll want to use abort, which also takes an optional string param that will get outputted on exit:
task :check do
# If any of your checks fail, you can exit early like this.
abort( "One of the checks has failed!" ) if check_failed?
end
On the command line:
$ rake che...