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Error while installing json gem 'mkmf.rb can't find header files for ruby'
...installing command-line tools and accepting the license with
sudo xcode-select --install
sudo xcodebuild -license accept
The issue is that Xcode 11 ships the macOS 10.15 SDK which includes headers for ruby2.6, but not for macOS 10.14's ruby2.3. You can verify that this is your problem by runnin...
How to implement custom JsonConverter in JSON.NET to deserialize a List of base class objects?
...o match a divierd class based on the class given to the serilaizer
/// Selected class will be the first class to match all properties in the json object.
/// </summary>
public class KnownTypeConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
...
Fixing “Lock wait timeout exceeded; try restarting transaction” for a 'stuck" Mysql table?
...
You can check the currently running transactions with
SELECT * FROM `information_schema`.`innodb_trx` ORDER BY `trx_started`
Your transaction should be one of the first, because it's the oldest in the list. Now just take the value from trx_mysql_thread_id and send it the KILL ...
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...int, unique key (u));
mysql> insert into foo (u) values (10);
mysql> select * from foo;
+----+------+
| id | u |
+----+------+
| 1 | 10 |
+----+------+
mysql> show create table foo\G
CREATE TABLE `foo` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`u` int(11) DEFAULT NULL,
...
How do I perform the SQL Join equivalent in MongoDB?
...background as well, I would appreciate MongoDB taking a 'result set' (with selected returned fields) as input for a new query in one go, much like nested queries in SQL
– Stijn Sanders
Nov 26 '10 at 23:17
...
How can I use Async with ForEach?
...ext db = new DataLayer.DataContext())
{
var tasks = db.Groups.ToList().Select(i => GetAdminsFromGroupAsync(i.Gid));
var results = await Task.WhenAll(tasks);
}
The benefits of this approach over giving an async delegate to ForEach are:
Error handling is more proper. Exceptions from asy...
ReSharper - force curly braces around single line
...f-else" statement" to "Use braces for multiline"
After saving the changes, select a scope to reformat (could be a code selection, file, folder, project, solution - anything you want).
Choose ReSharper > Tools > Cleanup Code.
Profit.
Remember that Code Cleanup does numerous things and they're...
Which version of MVC am I using?
...
Select the System.Web.Mvc assembly in the "References" folder in the solution explorer. Bring up the properties window (F4) and check the Version
...
How can I determine what font a browser is actually using to render some text?
...that, but Safari needs you to copy some text and investigate that.
First, select some text. In Firefox, the Page Inspector has a Fonts view:
This will also tell you if fonts were downloaded, and which style is used, such as Regular, ExtraLight, Italic, BoldItalic and all.
For Chrome, go into De...
Split string, convert ToList() in one line
...
var numbers = sNumbers.Split(',').Select(Int32.Parse).ToList();
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