Visual Studio Does not recognize System.Linq

Question

I created this program and C# and it worked correctly a few weeks ago. Now, I copied all of this code to a another project I am working on. I added it to a brand new C# Cla

Answer 1

• Step 1) Go to your Project Solution Explorer and Select References
• Step 2) Right click it on References and Select Add Reference... a form will appear
• Step 3) Search linq on Search bar
• Step 4) Now Select/tick the System.XML.Linq checkbox
• Step 5) Click Ok

Answer 2

I had a similar issue. I upgraded my asp.net project to .NET Framework 4.5.x and it worked. I did tried 4.5.1 first and then later 4.5.0 and both seem to be helping.

Answer 3

An educated guess: It's probably the .NET framework target version of the new project.

System.Linq was introduced on .NET Framework 3.5.

Go to Project -> Properties -> Application and check the Target Framework property. It's probably a target framework prior to 3.5

Answer 4

For me I tried this and worked:

PROJECT==>Add Reference ==> Browse ==> C:\Windows\winsxs\x86_netfx35linq-system.core_31bf3856ad364e35_6.1.7601.17514_none_6161fc35ed136622\System.core.dll

Or

you can simply find the System.core.dll using windows search on Os System Drive

Answer 5

You need to add refrence to system.Core.

Answer 6

You need to right click on the solution in Solution Explorer and add a reference to System.Xml.Linq and/or System.Linq in Project Properties.

This has hit me several times - I see it a lot with System.Configuration as well. (For some reason those two references seem to be particularly picky)