Develop Reference

Type or namespace name 'xxx' could not be found in Umbraco

When I created a class, there is no existing namespace declaration and I need the namespace declaration to access the class from a view (cshtml).
Normally when you create a class, there should be a namespace declaration included right? But for me I don't see any.
I already tried to add a namespace declaration, but I still can't access it from another class.
I hope you could help me with this.
Screenshots: https://drive.google.com/open?id=0B5TGcf9mTeg2V2ZDaldWelp6WXc
ScreenShot

make sure your namespace name is correct .using PRL(Capitalized) .Models .And the good practice is add an empty web application project ,not a website.

Just as what Nico Said (https://stackoverflow.com/users/5685258/nico)
Follow this instructions and this will be resolved:
https://our.umbraco.org/documentation/Getting-Started/Setup/Install/install-umbraco-with-nuget
Although I started all over again.
~I created a new project from Visual Studio 2017 using ASP.NET Web Application
~Selected an empty file
~ Right click on the project
~ Click Manage NuGet Packages and installed Umbraco CMS
~ Run it from VS and install the umbraco platform using the browser
~ As soon as I create a class, a namespace declaration will also be included.
Thanks!

Your model belongs to namespace PRL.Models but you try using Prl.Models - namespaces are case-sensitive. Try using PRL.Models
Edit: and for the class without namespace-declaration: you should always have a class in a namespace. Declare one.

I can't use ActiveUp.MailSystem.Net

I'm trying to use ActiveUp.MailSystem.Net which I downloaded from here:
https://mailsystem.codeplex.com/
I added all the dll-s through the add reference option. Now Using ActiveUp, Using ActiveUp.Net are working, but for the Using ActiveUp.Net.Mail I get the error The type or namespace name 'Mail' does not esist in..... I also added the dll-s to the resources but no luck. What makes me that noob?
P.S.: I'm using Visual Studio Express C# 2010

Where to search for Microsoft.TeamFoundation.Framework.Client

Hi does any of you know where can I find Microsoft.TeamFoundation.Framework.Client using nuget? I can't find it because I'm trying to create instance of TfsConfigurationServer.

The namespace "Microsoft.TeamFoundation.Framework.Client" is in the Microsoft.TeamFoundation.Client.dll.

These assemblies are shipped with visual studio for vs2013 located under the extensions tab.
see the following for an example of how to use the .dll's in a console application
http://msdn.microsoft.com/en-us/library/bb286958.aspx

ManagementObject Class not showing up in System.Management namespace

I'm trying to write some WMI in my windows form and the ManagementObject is givin me the
"The type or namespace name 'ManagementObject' could not be found" Error
Here is my un-complete code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Threading;
using System.Security.Policy;
using System.Management;
using System.Management.Instrumentation;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
ManagementObject disk = new ManagementObject("Win32_LogicalDisk.DeviceID=\"C:\"");

Right-click References on the right and manually add System.Management. Even though I included it in the using statement I still had to do this. Once I did, all worked fine.

Have you added a reference to the System.Management assembly?

In Solution Explorer, right click on References, then Add Reference ... and under Framework, you should activate the System.Management framework.

You need to add a reference to System.Management.dll to your project.
You can see System.Management.Instrumentation without adding a reference to System.Management.dll because it is included in a different library (System.Core.dll, which is included as a reference automatically), but you cannot access the other types contained by that namespace without explicitly adding a reference to the System.Management.dll library.

~ just add System.management using nuget manager,
It worked for me! c#

I think the problem is there is no WMI object for Win32_LogicalDisk.DeviceID=\"C:\".
Try to replace:
ManagementObject disk = new ManagementObject("Win32_LogicalDisk.DeviceID=\"C:\"");
with:
ManagementObject disk = new ManagementObject("Win32_LogicalDisk");
and then to step through each field:
foreach (ManagementObject o in disk.Get()){
//Do what ever you need here.... For example:
Console.WriteLine(o.ToString());
}

Make sure your project isn't set up to compile against the .NET 4 Framework Client Profile.
Please see Namespace not recognized (even though it is there) for more details.

The version of Visual Studio that I have does not import ManagementObjectSearcher by importing "System.Management" namespace. If you have the same issue, try adding a reference to "System.Management.dll' by doing the following steps.
Click on project properties on solution explorer in Visual Studio.
Go to "References".
Click on "Add" to add a new reference.
Click on "Browse...".
Navigate to "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727".
Add a reference to "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Management.dll".

This is quite an old post but I just had to troubleshoot this. The only way I got it working with Visual Basic 2022 was to download and install through the NuGet Installer. Manually adding the .dll did not work for me. Once NuGet Manager is open Search: System.Management and download the latest from Microsoft, hope this helps someone.

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.