Develop Reference

In Visual Studio is there a way to define a using statement for the whole project? ex. using Random = UnityEngine.Random; for every .cs file?

I consistently am dealing with ambiguous references between System.Random and UnityEnginge.Random. To address this I need to add the "using Random = UnityEngine.Random;" to each file. I was curious if instead I could somehow set Random to always use the UnityEngine namespace for the whole project by default.
Manually changing every file seems to be the only solution I could find.

You can use global using statements. The global using directive is a new feature that was recently added to C# language in C# version 10.0. This feature allows to declare a namespace globally in any one of the files in a project and the global declared namespace is imported and available to all files in the application
EX:
global using System.IO;

why we give reference to the other projects?

When looking at a solution with multiple projects:
1) Why do we add a reference to the other project? Can't we just use inheritance?
2) After we add the reference by using Visual Studio, why do we have to add the project to the namespace system? For example: using myReferenceProject; I thought that the IDE would do that.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using myReferenceProject;
using System.Data.SqlClient;
using System.Data;

1) why we give reference to the other project? cant we just use inheritance???
They're two completely different concepts.
Adding a reference to another assembly basically says, "I want to be able to use some of this code. Please make the compiler aware that this code exists, and optionally copy it into the output directory so that it's present at execution time too."
How would you expect to use inheritance to create a class derived from some type if the compiler has no knowledge of that type?
2) after we give the reference by using the visual studio IDE why we have to add the project to the namespace system???
Because assemblies and namespaces are different concepts too. A using directive simply says to the compiler "When I refer to type Foo within my code, look in these namespaces to try to resolve it." That type could come from any of the assemblies you've referenced.
It's really important that you understand the difference between assemblies and namespaces. Even though they're often named similarly (Foo.Bar.dll often provides types in the namespace Foo.Bar) they're conceptually different.

The project is a self sufficent compilable unit, that has to compile into the valid assembly file. That's why you need esplicitly specifiy which referencies every project needs in order to be able to compile separately from others.
There is no any inheritance concept on projects level.

1) why we give reference to the other project? cant we just use inheritance?
This question makes no sense. What does inheritance have to do with project references. Can you elaborate?
2) after we give the reference by using the visual studio IDE why we have to add the project to the namespace system?
Because there's an inherent difference between an assembly referencing another assembly (which is what happens when you add a reference to the project) and the language knowing where to find a class which is what happens when you use the using directive in a file.
For example, suppose you create a class in your project called TextBox. Then in another file you want to use that class. How would the language know whether you are referring to your custom TextBox class or another one in a referenced assembly? The answer to that question is namespaces. By fully-qualifying the class name with its namespaces, you tell the compiler which class you're using.
The using directive is a way to specifying the namespace once per file instead of every time you use the class (or other classes in that namespace). So if you need to reference your TextBox class multiple times within a single file, you wouldn't want to have to write this every time:
MyCodebase.MyAssembly.MyNamespace.MyOtherNamespace.SomethingElse.TextBox
Instead, you include a using directive of the entire namespace, so you only have to write this:
TextBox

Properly remove StyleCop R# plugin

I installed StyleCop and the associated plugin for ReSharper 5. After getting annoyed with it I removed both the plugin and StyleCop, but ReSharper is still using some of the StyleCop behaviour - most notably moving using statements to within the namespace declaration, rather than keeping them outside the declaration.
For instance say you have the following source:
using System;
using System.Web;
namespace Foo.Bar
{
////
}
And the file sits within The Foo/Bar/Widget directory, using ReSharper's fix namespace tool I would expect the file to stay the same, but the namespace to have changed to Foo.Bar.Widgets (this is the behaviour it exhibited before StyleCop came along).
Now however it rearranges the file:
namespace Foo.Bar.Widget
{
using System;
using System.Web;
////
}
Now putting aside people's personal preferences about which one is better, I don't like it, and it is inconsistent with our existing code. Having to manually move using statements after renaming the namespace takes long than renaming the namespace manually.
Does anyone know how to correct this (I'm assuming there is a file or something still lingering around from the install, or a config that hasn't been reverted).

You can change it here:
ReSharper -> Options -> Languages -> C# -> Namespace Imports -> Add using directive to the deepest scope
UPDATE - Resharper 9 This option is now moved to:
ReSharper -> Options -> Code Editing -> C# -> Code Style -> Reference qualification

I just had the same issue. It turns out that the StyleCop settings are stored in the "This computer" layer of ReSharper settings. See ReSharper > Manage Options for a list of layers.
I just had to reset the "This computer" layer; this was possible since I had never intentionally modified it.

namespace or class could not be found (ASP.NET WebSite "project")

I am currently trying to cleanup a bit of a corporate website that I inherited here. I managed to clean up most of the errors in the website but something is still up here.
I have one masterpage that have this code :
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.ComponentModel;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class MasterPage : System.Web.UI.MasterPage {
public lists m_listsClass = new lists();
(no it's not a typo the S in lists).
Now in App_code I have one class lists.cs
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
/// <summary>
/// Summary description for lists
/// </summary>
public class lists
{
public lists()
{
When I try to build the website in visual studio 2008 I have this error :
Error 3 The type or namespace name 'lists' could not be found (are you missing a using directive or an assembly reference?) C:\Users\egirard\Documents\Visual Studio 2008\Projects\iFuzioncorp\iFuzioncorp\Masters\MasterPage.master.cs 23 12 iFuzioncorp
Am I missing something ?
Also I saw some strange behaviour on the server. Apparently according to IIS7 it is compiling using .net 2.0 (the pool is configured with .net 2) but there are some "using" statements that include Linq ... how is it possible to compile the page if Linq is not part of the .net 2 itself ?
Just edited with news details on the code itself. No namespace at all everywhere.

Hi There – i had a similar problem; all my namespaces and inheritance was in place. Then i then noticed that the class file’s build action was set to “Content” not “Compile” (in the properties window.

For whatever worth might there be for an answer (possibly not the right one) after many months, i think i should contribute this:
There is a case that this happens, when you place a web site inside another (ie in a subfolder).
In that case, the only App_Code folder that is legitimate is the App_code folder of the outer web site. That is, the App_Code folder right under the root of the master web site.
Maybe (say maybe) there should be no need to transform your web site to a web application, if you place the class file inside the App_code folder of the ROOT web site.

include the namespace under which lists calss is defined
or
define both the master page and lists class under the same namespace

Finally I understood quite lately that it was a website and not a web application I had to question the guys here to get it... So it's quite normal all the error I had. I haven't had the occasion to convert it first.

Make sure that in your masterpage, you have an #include statement for the namespace that the lists class is a part of (if they're in seperate namespaces, the masterpage isn't going to automatically pick up on it).
As for the strange server side behavior, .NET 2.0, 3.0, and 3.5 all run inside of .NET 2.0 app pools in IIS. It looks strange at first, but you get used to it. Here's a link with a little more in-depth explination:
The Way I See It: Where is ASP.NET 3.5 on IIS?

In order to use a type, you must reference the assembly which defines it and include the appropriate namespace.
Using only includes namespaces, if you don't use any types from said namespaces it has no effect.

is lists.cs wrapped in a namespace? if it is the case then you need to add the namespace (yournamespace.lists) or include it in masterpage. Check Also if your MasterPage is in a Namespace

Modify the Build Action of the App_Code Class to Compile.
Clean and Build the Project
This worked for me.

I had this problem myself
It wasn't working because the project I was referencing was set as a console application in its properties instead of a class library

System.Windows.Forms.DataVisualization Namespace Fine in One Class but Not in Another

I'm getting this error
The type or namespace name 'DataVisualization' does not exist in the namespace 'System.Windows.Forms' (are you missing an assembly reference?)
Here is my using section of the class:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Windows.Forms.DataVisualization.Charting;
using System.Windows.Forms.DataVisualization.Charting.Borders3D;
using System.Windows.Forms.DataVisualization.Charting.ChartTypes;
using System.Windows.Forms.DataVisualization.Charting.Data;
using System.Windows.Forms.DataVisualization.Charting.Formulas;
using System.Windows.Forms.DataVisualization.Charting.Utilities;
namespace myNamespace {
public class myClass {
// Usual class stuff
}
}
The thing is that I am using the same DataVisualization includes in another class. The only thing that I can think that is different is that the classes that are giving this missing namespace error are Solution Items rather than specific to a project. The projects reference them by link. Anyone have thoughts on what the problem is? I've installed the chart component, .Net 3.5 SP1, and the Chart Add-in for Visual Studio 2008.
UPDATE: I moved the items from Solution Items to be regular members of my project and I'm still seeing the same behavior.
UPDATE 2: Removing the items from the Solution Items and placing them under my project worked. Another project was still referencing the files which is why I didn't think it worked previously. I'm still curious, though, why I couldn't use the namespace when the classes were Solution Items but moving them underneath a project (with no modifications, mind you) instantly made them recognizable. :\

You are very likely missing a reference to the DataVisualization DLL. Note that although they share the namespace of System.Windows.Forms.dll, they aren't actually contained within it.

Solution items aren't used by compiled assemblies.
http://msdn.microsoft.com/en-us/library/1ee8zw5t.aspx
"They can be referenced by projects, but are never included in solution or project builds"
As far as I know, solution folders/items are really just meant for organizing things.

Are you getting actual build errors or just squiggles? Try building and look at the output window, does it succeed or fail?
In VS 2008 SP1 C# introduced a top level error squiggling feature. It's possible that if you open the solution item version of the file it will squiggle because of a lack of default references. The solution should still build correctly though.
If this is not the case try adding the file directly to the project (no link). See if that eliminates the error. If so then we know it has to due with a linked file and it can help track down the problem.