Questions tagged [.net]
Do NOT use for questions about .NET Core - use [.net-core] instead. The .NET framework is a software framework designed mainly for the Microsoft Windows operating system. It includes an implementation of the Base Class Library, Common Language Runtime (commonly referred to as CLR), Common Type System (commonly referred to as CTS) and Dynamic Language Runtime. It supports many programming languages, including C#, VB.NET, F# and C++/CLI.
47,026
questions
1874
votes
28answers
1.6m views
What is a NullReferenceException, and how do I fix it?
I have some code and when it executes, it throws a NullReferenceException, saying:
Object reference not set to an instance of an object.
What does this mean, and what can I do to fix this error?
200
votes
4answers
209k views
What is an IndexOutOfRangeException / ArgumentOutOfRangeException and how do I fix it?
I have some code and when it executes, it throws a IndexOutOfRangeException, saying,
Index was outside the bounds of the array.
What does this mean, and what can I do about it?
Depending on ...
1474
votes
47answers
716k views
How do I update the GUI from another thread?
Which is the simplest way to update a Label from another Thread?
I have a Form running on thread1, and from that I'm starting another thread (thread2).
While thread2 is processing some files I would ...
1132
votes
8answers
283k views
How do I use reflection to call a generic method?
What's the best way to call a generic method when the type parameter isn't known at compile time, but instead is obtained dynamically at runtime?
Consider the following sample code - inside the ...
1522
votes
22answers
234k views
What is the best algorithm for overriding GetHashCode?
In .NET, the GetHashCode method is used in a lot of places throughout the .NET base class libraries. Implementing it properly is especially important to find items quickly in a collection or when ...
2375
votes
49answers
867k views
Deep cloning objects
I want to do something like:
MyObject myObj = GetMyObj(); // Create and fill a new object
MyObject newObj = myObj.Clone();
And then make changes to the new object that are not reflected in the ...
908
votes
22answers
591k views
Sending email in .NET through Gmail
Instead of relying on my host to send an email, I was thinking of sending the email messages using my Gmail account. The emails are personalized emails to the bands I play on my show.
Is it possible ...
1034
votes
28answers
837k views
Deserialize JSON into C# dynamic object?
Is there a way to deserialize JSON content into a C# 4 dynamic type? It would be nice to skip creating a bunch of classes in order to use the DataContractJsonSerializer.
1989
votes
46answers
1.2m views
How do I create an Excel (.XLS and .XLSX) file in C# without installing Microsoft Office?
How can I create an Excel spreadsheet with C# without requiring Excel to be installed on the machine that's running the code?
915
votes
14answers
512k views
How do I force my .NET application to run as administrator?
Once my program is installed on a client machine, how do I force my program to run as an administrator on Windows 7?
66
votes
15answers
474k views
What is the best way to parse html in C#? [closed]
I'm looking for a library/method to parse an html file with more html specific features than generic xml parsing libraries.
885
votes
20answers
584k views
Is there a way to check if a file is in use?
I'm writing a program in C# that needs to repeatedly access 1 image file. Most of the time it works, but if my computer's running fast, it will try to access the file before it's been saved back to ...
719
votes
29answers
725k views
2179
votes
18answers
1.0m views
Difference between decimal, float and double in .NET?
What is the difference between decimal, float and double in .NET?
When would someone use one of these?
1738
votes
19answers
355k views
Proper use of the IDisposable interface
I know from reading the Microsoft documentation that the "primary" use of the IDisposable interface is to clean up unmanaged resources.
To me, "unmanaged" means things like database connections, ...
1266
votes
15answers
1.9m views
How to make an HTTP POST web request
Canonical
How can I make an HTTP request and send some data using the POST method?
I can do a GET request, but I have no idea of how to make a POST request.
1171
votes
25answers
951k views
How and when to use ‘async’ and ‘await’
From my understanding one of the main things that async and await do is to make code easy to write and read - but is using them equal to spawning background threads to perform long duration logic?
I'...
631
votes
11answers
504k views
How do you do a deep copy of an object in .NET? [duplicate]
I want a true deep copy. In Java, this was easy, but how do you do it in C#?
374
votes
30answers
318k views
What Are Some Good .NET Profilers?
What profilers have you used when working with .net programs, and which would you particularly recommend?
185
votes
2answers
57k views
Understanding garbage collection in .NET
Consider the below code:
public class Class1
{
public static int c;
~Class1()
{
c++;
}
}
public class Class2
{
public static void Main()
{
{
var c1=...
6866
votes
63answers
1.2m views
What is the difference between String and string in C#?
Example (note the case):
string s = "Hello world!";
String s = "Hello world!";
What are the guidelines for the use of each? And what are the differences?
685
votes
34answers
328k views
Implementing INotifyPropertyChanged - does a better way exist?
Microsoft should have implemented something snappy for INotifyPropertyChanged, like in the automatic properties, just specify {get; set; notify;}
I think it makes a lot of sense to do it. Or are there ...
303
votes
21answers
408k views
Upload files with HTTPWebrequest (multipart/form-data)
Is there any class, library or some piece of code which will help me to upload files with HTTPWebrequest?
Edit 2:
I do not want to upload to a WebDAV folder or something like that. I want to ...
100
votes
14answers
91k views
What is the difference between a reference type and value type in c#?
Some guy asked me this question couple of months ago and I couldn't explain it in detail. What is the difference between a reference type and a value type in C#?
I know that value types are int, bool,...
681
votes
37answers
226k views
What is the correct way to create a single-instance WPF application?
Using C# and WPF under .NET (rather than Windows Forms or console), what is the correct way to create an application that can only be run as a single instance?
I know it has something to do with some ...
18
votes
2answers
24k views
MSI vs nuget packages: which are is better for continuous delivery?
Let's discuss following topic. There is application which currently is being deployed with good to know xcopy method.This approach makes difficult to manage dependencies, file updates etc. There is ...
851
votes
13answers
473k views
How to enable assembly bind failure logging (Fusion) in .NET
How do I enable assembly bind failure logging (Fusion) in .NET?
1991
votes
64answers
666k views
How do I calculate someone's age based on a DateTime type birthday?
Given a DateTime representing a person's birthday, how do I calculate their age in years?
1509
votes
27answers
202k views
Why not inherit from List<T>?
When planning out my programs, I often start with a chain of thought like so:
A football team is just a list of football players. Therefore, I should represent it with:
var football_team = new ...
652
votes
15answers
1.1m views
Run Command Prompt Commands
Is there any way to run command prompt commands from within a C# application? If so how would I do the following:
copy /b Image1.jpg + Archive.rar Image2.jpg
This basically embeds an RAR file ...
460
votes
20answers
227k views
How do I remove diacritics (accents) from a string in .NET?
I'm trying to convert some strings that are in French Canadian and basically, I'd like to be able to take out the French accent marks in the letters while keeping the letter. (E.g. convert é to e, so ...
695
votes
32answers
1.6m views
How can I convert String to Int?
I have a TextBoxD1.Text and I want to convert it to an int to store it in a database.
How can I do this?
758
votes
23answers
642k views
How to read embedded resource text file
How do I read an embedded resource (text file) using StreamReader and return it as a string? My current script uses a Windows form and textbox that allows the user to find and replace text in a text ...
243
votes
22answers
402k views
MVVM: Tutorial from start to finish?
I'm a C#/Windows Forms programmer with more than 5 years experience. I've been investigating WPF using the MVVM (Model-View-ViewModel) design pattern. I have searched the Internet for tutorials. I ...
615
votes
39answers
1.2m views
How do I make a textbox that only accepts numbers?
I have a windows forms app with a textbox control that I want to only accept integer values. In the past I've done this kind of validation by overloading the KeyPress event and just removing ...
12
votes
2answers
17k views
Why saving changes to a database fails?
I have following C# code in a console application.
Whenever I debug the application and run the query1 (which inserts a new value into the database) and then run query2 (which displays all the ...
271
votes
4answers
128k views
Entity Framework and Connection Pooling
I've recently started to use the Entity Framework 4.0 in my .NET 4.0 application and am curious about a few things relating to pooling.
Connection pooling as I know is managed by the ADO.NET data ...
1
vote
4answers
7k views
Windows service NOT shown in add remove programs under control panel
I installed my windows service via (name of the service: Testing Service)
InstallUtil.exe present in .NET Framework
(:\Windows\Microsoft.NET\FrameWork64\v4) in a windows 7 computer.
I can see my ...
279
votes
7answers
46k views
What is the purpose of “return await” in C#?
Is there any scenario where writing method like this:
public async Task<SomeResult> DoSomethingAsync()
{
// Some synchronous code might or might not be here... //
return await ...
47
votes
3answers
39k views
What do Option Strict and Option Explicit do?
I saw this post:
Typos… Just use option strict and explicit please.. during one software development project, which I was on as a consultant, they were getting ridiculous amounts of errors ...
232
votes
32answers
490k views
Reading Excel files from C#
Is there a free or open source library to read Excel files (.xls) directly from a C# program?
It does not need to be too fancy, just to select a worksheet and read the data as strings. So far, I've ...
195
votes
6answers
89k views
Pass An Instantiated System.Type as a Type Parameter for a Generic Class
The title is kind of obscure. What I want to know is if this is possible:
string typeName = <read type name from somwhere>;
Type myType = Type.GetType(typeName);
MyGenericClass<myType> ...
142
votes
7answers
260k views
How do you do Impersonation in .NET?
Is there a simple out of the box way to impersonate a user in .NET?
So far I've been using this class from code project for all my impersonation requirements.
Is there a better way to do it by using ...
26
votes
2answers
14k views
Why does WPF support binding to properties of an object, but not fields?
I've got a WCF service that passes around status updates via a struct like so:
[DataContract]
public struct StatusInfo
{
[DataMember] public int Total;
[DataMember] public string Authority;
}
...
658
votes
16answers
422k views
Embedding DLLs in a compiled executable
Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, how would one go about doing it?
Normally, I'm cool with ...
589
votes
18answers
333k views
C# difference between == and Equals()
I have a condition in a silverlight application that compares 2 strings, for some reason when I use == it returns false while .Equals() returns true.
Here is the code:
if (((ListBoxItem)lstBaseMenu....
2259
votes
40answers
1.2m views
How do I get a consistent byte representation of strings in C# without manually specifying an encoding?
How do I convert a string to a byte[] in .NET (C#) without manually specifying a specific encoding?
I'm going to encrypt the string. I can encrypt it without converting, but I'd still like to know ...
483
votes
16answers
231k views
Can't specify the 'async' modifier on the 'Main' method of a console app
I am new to asynchronous programming with the async modifier. I am trying to figure out how to make sure that my Main method of a console application actually runs asynchronously.
class Program
{
...
859
votes
25answers
252k views
ASP.NET Web Site or ASP.NET Web Application?
When I start a new ASP.NET project in Visual Studio, I can create an ASP.NET Web Application or I can create an ASP.NET Web Site.
What is the difference between ASP.NET Web Application and ASP.NET ...
651
votes
12answers
155k views
C# Interfaces. Implicit implementation versus Explicit implementation
What are the differences in implementing interfaces implicitly and explicitly in C#?
When should you use implicit and when should you use explicit?
Are there any pros and/or cons to one or the other?...