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Questions tagged [c#-4.0]

C# 4.0 introduced features like dynamic objects, COM interoperability improvements, generic co- and contra-variance, optional and named parameters. Use this tag if your question specifically pertains to C# 4.0 specific features. The C# tag should be used if your question is not specific to C# 4.0 features.

C# 4.0 is the fourth version of the programming language. It introduced features like dynamic objects, COM interoperability improvements, and optional and named parameters.

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25854 questions
724
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10 answers

Interop type cannot be embedded

I am creating a web application on the .NET 4.0 framework (beta2) in C#. When I try to use a assembly called "ActiveHomeScriptLib", I get the following error: Interop type 'ActiveHomeScriptLib.ActiveHomeClass' cannot be embedded. Use the…
Jan
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640
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10 answers

What are the true benefits of ExpandoObject?

The ExpandoObject class being added to .NET 4 allows you to arbitrarily set properties onto an object at runtime. Are there any advantages to this over using a Dictionary, or really even a Hashtable? As far as I can tell, this is…
Reed Copsey
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435
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8 answers

What is the difference between task and thread?

In C# 4.0, we have Task in the System.Threading.Tasks namespace. What is the true difference between Thread and Task. I did some sample program(help taken from MSDN) for my own sake of learning with Parallel.Invoke Parallel.For Parallel.ForEach…
user372724
414
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7 answers

Why are C# 4 optional parameters defined on interface not enforced on implementing class?

I noticed that with the optional parameters in C# 4 if you specify an optional parameter on an interface you don't have to make that parameter optional on any implementing class: public interface MyInterface { void TestMethod(bool flag =…
theburningmonk
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363
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6 answers

.NET NewtonSoft JSON deserialize map to a different property name

I have following JSON string which is received from an external party. { "team":[ { "v1":"", "attributes":{ "eighty_min_score":"", "home_or_away":"home", "score":"22", …
RasikaSam
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319
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19 answers

Better naming in Tuple classes than "Item1", "Item2"

Is there a way to use a Tuple class, but supply the names of the items in it? For example: public Tuple GetOrderRelatedIds() That returns the ids for OrderGroupId, OrderTypeId, OrderSubTypeId and OrderRequirementId. It would be…
Vaccano
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294
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5 answers

Dynamically adding properties to an ExpandoObject

I would like to dynamically add properties to a ExpandoObject at runtime. So for example to add a string property call NewProp I would like to write something like var x = new ExpandoObject(); x.AddProperty("NewProp", System.String); Is this easily…
Craig
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280
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4 answers

Parallel.ForEach vs Task.Factory.StartNew

What is the difference between the below code snippets? Won't both be using threadpool threads? For instance if I want to call a function for each item in a collection, Parallel.ForEach(items, item => DoSomething(item)); vs foreach(var item…
stackoverflowuser
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276
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10 answers

What is the 'dynamic' type in C# 4.0 used for?

C# 4.0 introduced a new type called 'dynamic'. It all sounds good, but what would a programmer use it for? Is there a situation where it can save the day?
Fahad
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247
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11 answers

C# 4.0 optional out/ref arguments

Does C# 4.0 allow optional out or ref arguments?
Joe Daley
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224
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12 answers

HttpListener Access Denied

I am writing an HTTP server in C#. When I try to execute the function HttpListener.Start() I get an HttpListenerException saying "Access Denied". When I run the app in admin mode in windows 7 it works fine. Can I make it run without admin mode?…
Randall Flagg
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214
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8 answers

C# Create New T()

You can see what I'm trying (but failing) to do with the following code: protected T GetObject() { return new T(); } Any help would be greatly appreciated. EDIT: The context was as follows. I was playing around with a custom controller class…
Hanshan
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204
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5 answers

How can I default a parameter to Guid.Empty in C#?

I wish to say: public void Problem(Guid optional = Guid.Empty) { } But the compiler complains that Guid.Empty is not a compile time constant. As I don’t wish to change the API I can’t use: Nullable
Ian Ringrose
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203
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3 answers

Is HttpClient safe to use concurrently?

In all the examples I can find of usages of HttpClient, it is used for one off calls. But what if I have a persistent client situation, where several requests can be made concurrently? Basically, is it safe to call client.PostAsync on 2 threads at…
Alex K
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198
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10 answers

Covariance and contravariance real world example

I'm having a little trouble understanding how I would use covariance and contravariance in the real world. So far, the only examples I've seen have been the same old array example. object[] objectArray = new string[] { "string 1", "string 2" }; It…
Razor
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