tag:blogger.com,1999:blog-58805616547095339462024-09-01T16:15:33.179-07:00Waldgeist's notesTiny notes from everyday work. Mostly about .NET, C# and some tools I use every day.Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.comBlogger49125tag:blogger.com,1999:blog-5880561654709533946.post-55066371580077550362021-03-22T04:58:00.003-07:002021-03-22T04:58:46.476-07:00Git config includeif Git config "includeif" feature works only in git initialized directories. On plain directories it uses only default .gitconfig file.Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-88049010042285648772020-02-10T01:10:00.002-08:002020-02-10T01:11:28.839-08:00Relative Uris and leading/trailing backslash
Be very accurate with leading and trailing backslashes in URLs. For instance, I have some app installed on http://some.host/path that provides api via relative uri /api/some/call
There is only one correct combination of Base and Rel Uris:
(4 items)4
Base
Rel
Result
http://some.host/path/
/api/some/call
http://some.host/api/some/call
http://some.host/path/
api/some/call
http://Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-24598543602782962112017-09-06T07:56:00.002-07:002017-09-06T07:56:48.735-07:00UriEncode
There are two static methods in System.Uri: EscapeDataString and EscapeUriString. Use first to escape any string after '?' in uri and second one to escape any string before '?':
Symbol EscapeUriString EscapeDataString
aaa
bbb
ccc
space%20%20
??%3F
!!%21
@@%40
##%23
$$%24
%%25%25
^%5E%5E
&&%26
**%2A
((%28
))%29
//%2F
\%5C%5C
++%2B
___
---
<%3C%3C
&Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-78572997625756334912017-07-21T01:25:00.002-07:002017-07-21T01:25:59.291-07:00ToArray vs ToList vs ToImmutableArray vs ToImmutableList
ToArray() is the fastest way to materialize IEnumerable on dotnet core:
BenchmarkDotNet=v0.10.8, OS=Mac OS X 10.12
Processor=Intel Core i7-4770HQ CPU 2.20GHz (Haswell), ProcessorCount=8
Frequency=1000000000 Hz, Resolution=1.0000 ns, Timer=UNKNOWN
dotnet cli version=1.0.4
[Host] : .NET Core 4.6.25211.01, 64bit RyuJIT
DefaultJob : .NET Core 4.6.25211.01, 64bit RyuJIT
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com2tag:blogger.com,1999:blog-5880561654709533946.post-63685109992630686902017-06-16T06:10:00.001-07:002017-06-16T06:59:10.182-07:00dotnet core + bash
To update all packages in all projects:
find . -name "*.csproj" -exec sh -c "gawk 'match(\$0, /PackageReference Include=\"(.*)\" Version/, a){print a[1]}' {} | xargs -L1 dotnet add {} package" \;
To run all tests in all Tests projects:
find . -name "*Tests*.csproj" -execdir dotnet test --no-build {} \;
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-37284470904528787462016-06-21T02:32:00.001-07:002016-06-21T02:32:24.510-07:00Nuget or not nuget
To switch all references from static dll to Nuget, use following snippet in Package Manager Console:
Get-Project -All | foreach-object {IF (Get-Content $_.FullName | Select-String "XXX") {Install-Package XXX -ProjectName $_.FullName}}
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-29658881842021751172015-03-09T06:54:00.001-07:002015-03-09T06:54:50.777-07:00Group by order
Quite a common case - assume we have a collection of items and we want to iterate over it, but at first by items with some feature, then by items without such feature.
For instance, we have list of integers and want to iterate firstly all even numbers, then all odd numbers.
First approach is to group items by this feature and then iterate over group:
var
ints = new[]{1,2,3,4,5};
var
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-80352606996069023972013-11-21T23:11:00.000-08:002013-11-21T23:11:12.190-08:00Assert T
Here is some trick for getting over type erasure in Scala.
I want to create the following method that will expect an exception of particular type:
def assertT[T <: Throwable ](body: =>Unit) = {
try {
body
assert(false)
} catch {
case e : T => assert(true)
}
}
But due to type erasure, the case condition ( : T ) will be never checked. Scala compiler will warn you Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-52660870596661466562013-05-19T04:38:00.001-07:002013-05-19T04:38:19.313-07:00Capital Eye
What will the following line print out?
Console.WriteLine("i".ToUpper());
The answer is obvious: "It depends"
String.ToUpper as well as string.ToLower will use current thread culture, and in most cases it will print "I", but there is two cultures, where capital "i" is not "I", but "İ" - Turkish (tr) and Azeri Latin (az-Latn).
So never ever use ToUpper() and ToLower() in internal Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-697977747657384832013-05-19T04:31:00.001-07:002013-05-19T04:32:10.287-07:00Compiled lambda issue
Never ever return the result of Expression<T>.Compile() method. If your compiled expression throws an exception, you will not get any info about the compiled lambda. For example, I have the NullReferenceException with following stack trace:
System.NullReferenceException: Object reference not set to an instance of an object.
at lambda_method(Closure , BugDto )
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-20677485643261530602012-10-15T03:37:00.000-07:002012-10-15T03:37:01.056-07:00Queryable extensions
It is possible to extend a LINQ vocabulary with some custom methods that will be used later in query providers to build a custom query to outer source. Also, there is a little trick that allows using such extensions in Linq-to-objects expressions.
Here is a standard stub for an IQueryable method:
public static IQueryable<Tuple<int, TKey>> CountBy<TSource, TKey>(this Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-19568318464238071472012-09-21T13:38:00.000-07:002012-09-21T13:38:30.452-07:00Pearls of scala I - By-name parameters
In C# there is no way to define short-circuit evaluated 'and' function (for example).
The naive implementation like following is not good enough.
bool And(bool a, bool b){
if (a)
return b;
else
return false;
}
Let define an identity function:
bool Id(bool value){
Console.WriteLine(value);
return value;
}
And let's compare Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-63147383120133083562012-05-30T01:02:00.000-07:002012-05-30T02:53:11.677-07:00MakeGenericType
When does the following line of code could fail with "The number of generic arguments provided doesn't equal the arity of the generic
type definition"?
var t = typeof (SomeGenericClass<,,>).MakeGenericType (typeof (int), typeof (int), typeof (int));
Where SomeGenericClass is defined as:
public class Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com2tag:blogger.com,1999:blog-5880561654709533946.post-68275009280235354312012-05-24T01:22:00.000-07:002012-05-24T01:22:08.633-07:00Reverse
Three tiny puzzles:
Given the following interface:
interface INode
{
INode Next { get; set; }
object Data { get; }
}
and a reference to root INode root reverse a one-linked list. Do not use any additional collections, as arrays, Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com6tag:blogger.com,1999:blog-5880561654709533946.post-63686622796891299992012-05-17T08:05:00.000-07:002012-05-17T23:40:16.298-07:00Mix of Queryable and Enumerable
Some useful observation from Expressions world.
Let's imagine we have the following class:
public class Foo
{
public int[] Items { get; set; }
}
And we use it in some IQueryable request in a following manner:
var queryable = new[] { new Foo {Items = new[] { 1, 2, 3 }} }Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-32626967655358225262012-05-08T05:42:00.000-07:002012-05-08T05:42:51.248-07:00Two cool regex features
Unicode Character Properties
\p{spec}
where spec - various specs definitions like:
L - letter
Ll - lowercase letter
P - punctuation
Cyrillic - Cyrillic letter
InSpecials: U+FFF0..U+FFFF
... and much more.
Character Class Subtraction
Example:
[a-z-[aeiuo]]
A single letter is not a vowel.
Could be combined with Unicode character properties:
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-18503325105314904952012-05-05T02:48:00.001-07:002012-05-05T02:48:40.360-07:00Delegate sum
Funny trick via http://confluence.jetbrains.net/display/ReSharper/Delegate+subtraction+has+unpredictable+semantics
Action a = () => Console.Write("A");
Action b = () => Console.Write("B");
Action c = () => Console.Write("C");
Action s = a + b + c + Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-2856413771298223942012-04-26T08:45:00.004-07:002012-05-01T02:33:03.817-07:00Private const
Some odd attribute defining behavior.
Let's define a class with some constants:
class Foo
{
public const string String = "some string";
protected const Type Type = null;
private const int Int =
42;
}
It's strange but you can access these constants inAlex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-25754981247733674012012-04-26T02:46:00.001-07:002012-04-26T02:46:44.499-07:00MyMacro
How to fix Visual Studio Macros IDE crashing from here:
2.1.7 On computers on which Visual Studio 2008 or SQL Server 2008 is installed and Visual Studio 2010 has been uninstalled and then reinstalled, using the Visual Studio Macros IDE may cause Visual Studio to crash
Uninstalling Visual Studio 2010 also removes the Visual Studio Macro Tools package. If the computer also has Visual Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-76523066128502127652012-04-25T02:59:00.003-07:002012-04-25T02:59:55.446-07:00Tail recursion
Some odd behavior to keep in mind.
The following code is expected to fail with StackOverflowException:
class Program
{
static void Main(string[]
args)
{
Tail();
}
&Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com2tag:blogger.com,1999:blog-5880561654709533946.post-87200791991360262842012-04-09T05:36:00.001-07:002012-04-19T06:09:06.734-07:00Lazy tree
Some stupid task about Expression trees.
Write down a simplest expression tree visitor (inherited from System.Linq.Expressions.ExpressionVisitor) that will have a static method:
public static IEnumerable<Expression>
All(Expression
node)
This method should return lazy enumeration of all expression in a an expression tree represented by node. By "lazy" I mean that a tree Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com2tag:blogger.com,1999:blog-5880561654709533946.post-22546067714101279672011-10-27T03:10:00.000-07:002011-10-27T03:10:23.877-07:00Serialization lost
Just a side note.
When an object is been deserialized by IFormatter, no constructors are called*! So if you have any fields marked as [NonSerialized] that are initilized in constructors or inline, they would not be initialized at all!
Consider the following example:
[Serializable]
public class Test
{
public Test()
{
Console.WriteLine("Inside ctor");
}
[NonSerializedAlex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-59501012828752094732011-10-26T12:49:00.000-07:002011-10-26T12:49:17.412-07:00Initialization trick
You all now the cool syntax sugar for object initialization in C#:
var item = new Item { Age = 5 };
Also there are sugar for collection initialization:
var items = new List<Item> { new Item { Age = 5 } };
And, of course, we could mix these two cases:
class ItemContainer
{
public List<Item> Items{get;set;}
}
// ...
var itemContainer = new ItemContainer Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-44488292888740964422011-09-28T05:01:00.000-07:002011-10-26T12:06:35.177-07:00Only one
Just another LINQ puzzle.
Let's assume that we have sequence of objects of type Item:
class Item
{
public int Age{get;set;}
}
How could you return all objects from the sequence that have Age value maximized (in a single LINQ query and single enumeration of the sequence)?
If the question was about returning the first object, the answer is straightforward:
return Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0tag:blogger.com,1999:blog-5880561654709533946.post-77658906624487759462011-09-20T07:02:00.000-07:002011-09-20T07:02:44.684-07:00Sexy sections
Configuration Section Designer is as awesome as simple. For example, here is scheme of our Visual Build board:
Alex Fominhttp://www.blogger.com/profile/02054479652706775847noreply@blogger.com0Minsk, Belarus53.904338156274704 27.465820312551.5890806562747 22.4121093125 56.219595656274706 32.5195313125