using Questions

1

The following code compiles with g++ 14.2 and clang++ 18.1, but fails with MSVC 17.10. class Base { public: using peak = Base; Base() = default; }; class Derived : public Base { protected: usin...

3

If the base class depends on the template parameter, its scope is not examined in the unqualified name lookup. I can use the using declaration to introduce names from the base class. Suppose now I ...
Monolatry asked 24/2, 2017 at 18:14

11

I need to force the use of "using" to dispose a new instance of a class. public class MyClass : IDisposable { ... } using(MyClass obj = new MyClass()) // Force to use "using" { }
Dikdik asked 20/4, 2010 at 13:38

6

Solved

Is it safe to use the using statement on a (potentially) null object? Consider the following example: class Test { IDisposable GetObject(string name) { // returns null if not found } void DoS...
Centrosymmetric asked 26/3, 2010 at 11:22

7

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In a MySQL JOIN, what is the difference between ON and USING()? As far as I can tell, USING() is just more convenient syntax, whereas ON allows a little more flexibility when the column names are n...
Recoil asked 6/7, 2012 at 16:16

4

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public class Abbreviation { public string ShortName { get; set; } public string LongName { get; set; } } I have a list of Abbreviation objects like this: List abbreviations = new List(); abb...
Colman asked 28/2, 2011 at 1:55

2

In a situation when some struct D inherits another struct A twice: once privately via B and the second time publicly via C, is it allowed to write using B::A in D? struct A {}; class B : A {}; stru...
Guanase asked 24/9, 2021 at 7:24

7

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With using namespace I make the whole contents of that namespace directly visible without using the namespace qualifier. This can cause problems if using namespace occurs in widely used headers - w...
Nonesuch asked 28/1, 2010 at 7:23

1

This question comes up a lot, is there any way to get Microsoft's attention and convince them to stop inserting this extremely annoying feature? If I have a C# file that doesn't currently use Syste...
Turk asked 10/3, 2023 at 15:52

3

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In C++, it's easy to write something along the lines of: #ifdef FAST typedef Real float; #endif #ifdef SLOW typedef Real double; #endif #ifdef SLOWER typedef Real quad; #endif In some common h...
Laughable asked 21/1, 2011 at 22:20

8

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First question: Say I have using (SqlConnection connection = new SqlConnection(connectionString)) { connection.Open(); string storedProc = "GetData"; SqlCommand command = new SqlCommand(store...
Nostomania asked 17/1, 2011 at 20:55

3

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https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/using#using-declaration The lifetime of a using local will extend to the end of the scope in which it is dec...
Adi asked 5/1, 2023 at 0:54

3

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Let's say I have a method foo which returns a ValueTuple where one of it's members is disposable, for example (IDisposable, int). What is the best way to make sure the returned disposable object i...
Coccidiosis asked 26/9, 2017 at 12:21

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I have a function in my code which only accepts a class member method as a template parameter. I need to call this method using a class method which is inherited from a parent class. Here is an exa...
Javed asked 4/5, 2022 at 11:10

1

In the following program, struct B has two user-defined constructors: one from int and another from int&& (clearly this is not very practical). And an object of B is created from an l-value...
Pester asked 6/2, 2022 at 8:47

4

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I have installed costura.fody into my project using nuget package. I have updated the FodyWeavers.xml file with: <Costura Unmanaged32Assemblies='dllname' Unmanaged64Assemblies='dllname' /> ...
Chock asked 13/11, 2015 at 15:6

1

I compiled the code below using g++ 6.3.0, with -std=c++14 option. #include <utility> #include <iostream> struct A{ int x; A(const A&)=default; A(int x):x(x){} }; struct B{ A ...
Arista asked 15/9, 2017 at 18:29

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class C { using namespace std; // error }; namespace N { using namespace std; // ok } int main () { using namespace std; // ok } I want to know the motivation behind it.
Decaliter asked 13/6, 2011 at 4:56

1

In a code like this using (var sftp = new SftpClient(_host, _userName, _password)) { sftp.Connect(); // Do some work with sftp sftp.Disconnect(); } Is sftp.Disconnect() call necessary or will...
Mediacy asked 6/1, 2017 at 17:42

6

I'm trying to define a pair of type aliases at the top of my C# program. This is a short example of what I'm trying to do: using System; using System.Collections.Generic; namespace Foo { using T...
Variation asked 10/3, 2016 at 16:17

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I was trying to learn and adopt the copy-swap idiom following this thorough explanation on this question: the Copy-Swap Idiom. But I found some code I had never seen: using std::swap; // all...
Buxtehude asked 24/1, 2011 at 13:44

3

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System.Windows.Markup.XamlParseExceptionoccurred A first chance exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll Additional information: 'Set pro...
Hessler asked 22/4, 2014 at 11:35

5

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I wrote the below code in order to explain my issue. If I comment the line 11 (with the keyword "using"), the compiler does not compile the file and displays this error: invalid conversion from 'ch...
Whizbang asked 13/12, 2009 at 15:32

2

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I use this command: sed -i "10 i \t\t\ttime.sleep(0.1) " /home/test_file to insert at line 10 a line like: <TAB><TAB><TAB>sleep(0.1) But I got t<TAB><TAB>sleep(0...
Autoroute asked 4/3, 2011 at 7:34

5

How can I use a variable outside the using statement ? I have this code: using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["batch"].ConnectionString)) { ...
Blowing asked 22/12, 2015 at 11:21

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