Questions tagged [method-group]
48 questions
8
votes
4 answers
why delegate must be static?
In code below I must declare method MdrResponseInterpreter static otherwise I have compilation error.
class.... {
private StandardBuilder _mdrResponseBuilder =
new StandardBuilder(MdrResponseInterpreter);
public static bool…
Oleg Vazhnev
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8
votes
2 answers
What is this ReSharper snippet 'convert to method group' actually doing?
Code before the changes:
List model = brands.Select(item => Mapper.Map(item)).ToList();
Code after the improvement:
List model = brands.Select(Mapper.Map
Only Bolivian Here
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8
votes
2 answers
Overloaded method-group argument confuses overload resolution?
The following call to the overloaded Enumerable.Select method:
var itemOnlyOneTuples = "test".Select>(Tuple.Create);
fails with an ambiguity error (namespaces removed for clarity):
The call is ambiguous between the following…
Ani
- 111,048
- 26
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6
votes
1 answer
Why does passing a method group to an overloaded method cause ambiguity when calling the method in a lambda does not in this case?
Why can't the correct overload to be called be inferred on the line marked // Compiler Error in the code below when the type is correctly inferred in all the other cases?
public static class Code {
private static void Main() {
…
Redwood
- 66,744
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4
votes
2 answers
Error Assigning Delegate Using ? : Syntax
I've created a delegate and two matching methods.
private delegate bool CharComparer(char a, char b);
// Case-sensitive char comparer
private static bool CharCompare(char a, char b)
{
return (a == b);
}
// Case-insensitive char…
Jonathan Wood
- 65,341
- 71
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- 466
4
votes
1 answer
Why doesn't the C# compiler resolve Delegate types only different in return type when passing a method group as parameter?
Please consider the following code:
class Program
{
static void Foobar() { }
static void Test(Action a) { }
static void Test(Func a) { }
static void Main(string[] args)
{
Test(Foobar);
}
}
It does not compile…
Imi
- 1,579
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4
votes
2 answers
C# delegate contravariance with lambda expression
The second test method below does not compile (cannot convert lambda expression to target type D1). Does that mean that (non-generic) delegate contravariance does not work with lambda expressions?
[TestFixture]
public class MyVarianceTests
{
…
mtraudt
- 103
- 4
3
votes
2 answers
Why does adding a return type prevent me from using method group syntax?
I'm trying to use a method group in a lambda expression, like this:
public class Foo { public void Hello(string s) { } }
void Test()
{
// this works as long as Hello has a void return type
Func> a = foo =>…
ladenedge
- 13,197
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3
votes
1 answer
C# LINQ - Does Select filter nulls when used with a method group?
Today I wrote some code that takes a list of class A instances and creates a list of class B instances using a static factory method:
public abstract class B
{
public static B CreateB(A a)
{
// return a new B instance or null if a B…
meir shapiro
- 647
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- 16
3
votes
0 answers
Method group conversions vs. boxing
I've created a struct named Point and a List of such points:
var myPoints = new List {
new Point() {Col = 3, Row = 2},
new Point() {Col = 2, Row = 4},
new Point() {Col = 5, Row = 4},
};
When I try to print them using ForEach()…
Mikhail Dudin
- 459
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3
votes
2 answers
Cannot Assign to 'Money' Because It Is a 'Method Group'
I'm doing a project for class, and I have to call the Money function from my Player class. However, I do not know how to change Money into something else that is not a Method Group. I don't know much programming, so my range of solutions is rather…
FCain 1026
- 59
- 2
- 6
3
votes
3 answers
When is it valid to say a method group conversion has taken place?
So i'm not really convinced when its safe to say that a method group conversion occured.
We have this multicast delegate from a previous post:
public partial class MainPage : PhoneApplicationPage
{
public delegate void MyDelegate(int a, int b);
//…
Freeman
- 5,691
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3
votes
7 answers
"<" operator error
Why is the ( i < UniqueWords.Count ) expression valid in the for loop, but returns "CS0019 Operator '<' cannot be applied to operands of type 'int' and 'method group'" error when placed in my if? They are both string arrays, previously declared.
for…
Nona Urbiz
- 4,873
- 16
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2
votes
2 answers
Pass a C# method group?
Is it possible to pass a method group as an argument in C#?
I am using a lot of mocks. I have the following:
public static List InvocationsWithName(
this Mock mock, string methodName)
where T: class
{
var invocations =…
William Jockusch
- 26,513
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2
votes
0 answers
How to prevent method group from discarding nullability of generic reference type?
Consider this generic identity function:
T Id(T x) => x;
If I use it in a lambda mapping the elements in an array of string? values, it works as expected (i.e. it preserves the information, that the values are nullable).
var xs = new[] {…
Good Night Nerd Pride
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