Develop Reference

MySql.Data.MySqlClient Reference Not Working in Visual Studio 2015

I've been attempting to connect a MySql database to my project in Visual Studio 2015. In order to connect it in the Server Explorer, I had to download and add the reference to my project. Easy peasy.
Then, when I attempted to follow this tutorial, I get this error message:
The type or namespace name 'MySqlConnection' could not be found (are you missing a using directive or an assembly reference?)
I have indeed added the assembly reference (I believe, if I understand the term correctly), by checking the MySql.Data in the References/Extension.
Am I using the wrong MySql.Data? How do I know which one? I've read that perhaps it can have to do with mixed versions of .NET Frameworks, but honestly I don't know how to check.
I'm an up-and-coming programmer, who before this, had only worked with static, hard-coded webpages, and never used databases in a project before.
EDIT: I have indeed added the 'using MySql.Data.MySqlClient to the same class file as I am attempting to use it in.
More information. What is displayed when I hover over the Data in MySql.Data.MySqlClient in the 'using' statements.

Your first screenshot shows the quickactions window suggesting that you use a fully qualified name, for the type, because it cannot determine where the type comes from.
Search to make sure that MySql.Data is not used, as a namespace, elsewhere in your project, so that it does not collide with the MySql.Data namespace from the dll you are referencing.

SGEN.exe - Microsoft.Xml namespace not found

I have a strange issue with my generated serialization .dll. The .dll is successfully generated I can reference it in my project, all the types are contained within the namespace Microsoft.Xml.Serialization.GeneratedAssembly as expected, even the intellisense is picking up the types and namespaces. But when I go to build the project referencing any of the types within the generated assembly I get an error along the lines of:
Error 2 The type or namespace name 'Xml' does not exist in the
namespace 'Microsoft' (are you missing an assembly reference?)
Rather odd, no? The namespace clearly exists as far as intellisense is concerned and I've never had an issue like this before. I tried to regenerate the assembly, still the same problem.
For now I have run sgen.exe with the flag /keep and just copied the generated source into my project which is fine. I was just curious if there was a way to fix this issue or if anyone else has ever come across it before.
EDIT:
It turns out that the issue is because the generated assembly is targeting a version of the .NET framework greater than the assembly that is referencing it. Now the question becomes - how do I generate a serialization assembly with Sgen that targets a specific .NET framework version.

Ok so after reading the answer on this question I managed to generate a serialization assembly that has the correct "runtime version" for .NET 3.5 and everything works as expected, sorry for wasting time.

Missing reference

In project i have reference to Microsoft.Office.Word.Server
and in code i have method that takes argument of type ConversionJob, but when i try to compile it i have an errors
The type or namespace name 'Office' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)
The type or namespace name 'ConversionJob' could not be found (are you missing a using directive or an assembly reference?)
but when a press f12 on ConversionJob it tooks me to the class defenition
using Microsoft.Office.Word.Server.Service;
using Microsoft.SharePoint;
using System;
namespace Microsoft.Office.Word.Server.Conversions
{
public class ConversionJob
{
public ConversionJob(WordServiceApplicationProxy serviceApplicationProxy, ConversionJobSettings settings);
public ConversionJob(WordServiceApplicationProxy serviceApplicationProxy);
...
what is wrong?
target framework is .Net framework 3.5
Solution
Ive solve the problem. I look to the output and there was message:
Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "<assembly reference>" could not be resolved because it has an indirect dependency on the framework assembly "<assembly" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v3.5". To resolve this problem, either remove the reference "<assembly>" or retarget your application to a framework version which contains "<assembly>"
i try to find solution in google and - > http://www.sanderstechnology.com/2011/warning-msb3268-you-are-about-to-experience-pain/10646/#.TtYrXGP20Z8

Check the target framework of your application, might be you´re building for the client profile but the referenced assembly requires the full framework.

Try changing the "Target Framework" to be ".NET Framework 4" instead of ".NET Framework 4 Client Profile".
Project Properties -> Application Tab -> Target Framework

You likely need to delete (MAKE SURE TO BACK IT UP) the 12.x.x.x .dll in your GAC folder, and make sure you are referencing the 14.x.x.x in your solution.

If you look at the project references, is it finding the assembly? The icon will look different if it can't resolve it.

1.Try to delete and then manualy add the reference (sometimes it helps - VS losting needed dll but not show it with another sign if not clean)
if 1. ok then backup and try to remove from GAC folder (to understatnd from where it calls assembly)

Probably you have a namespace or class with the name Office somewhere in your code. The compiler uses your namespace instead Office.
In other words I think you have a name collision with your project or any of the references you have in it.
Please investigate for overlapping namespaces / classes.

Referenced class lib doesn't seem

I have a class lib and I referenced it to another windows project. I added its namespace to my Form.cs (using SaglikNetClassLib;). they are seem unknown when I want to access to classes. I can see their properties and methods. But the complier says "Error 7 The type or namespace name 'SaglikNetClassLib' could not be found (are you missing a using directive or an assembly reference?), Do you have any suggestion?
KR,
Çağın

Are you targeting the .net Client Framework? Visual Studio let's you add references to incompatible assemblies, but then gives exactly that error.
Check your project settings to make sure you're targeting the full .net framework.
Also, check that the Ilalcar class is public and not internal (which is the default if it's only declared as class without any modifier)

You probably need an using statement to put the class into scope.
using SaglikNetClassLib;
C# won't auto suggest it if the project has not been rebuild. Also make sure the class library project has been build before using it in code.
Intellisense seems to lag behind a bit at times. Simply pressing f5 (run) sometimes rebuilds the project completely and simply runs or gives a better error message.

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.