Develop Reference

The type or namespace name does not exist in the namespace (are you missing an assembly reference?)

I know that this question has been already asked, but I cannot find anything that can help solve my problem.
I want to connect my aspx page (Retete.aspx) to a Microsoft SQL database. I'm getting this error on Retete.aspx.cs:
Error 1 The type or namespace name 'GlobalClass' does not exist in the namespace 'ProiectSera' (are you missing an assembly reference?)
The error points to this line of code:
ProiectSera.GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text);
Where ProiectSera is the project name, GlobalClass is the file where I make the operation on the db.
My using statements are:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ProiectSera;
The Target Framework is set to .net-4.5.
What should I do to solve this error?
Update
My GlobalClass.cs is:
using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;
using System.IO;
using ProiectSera;
using System.Data.Services;
namespace ProiectSera.App_Code
{
public static class GlobalClass
{
static public void Update(string _param1, string _param2)
{//function to update}
}
}
App_Code is a folder where GlobalClass.cs is. I tried and
ProiectSera.App_Code.GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text); //
but I had the same error. And I put the GlobalClass.cs in the project's root. I also removed the .App_Code from namespace ProiectSera.App_Code
UPDATE1
My Retete.aspx.cs is
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ProiectSera;
using ProiectSera.App_Code;
namespace ProiectSera
{
public partial class Retete : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnSave_Click(object sender, EventArgs e)
{
string intValRefTempSol;
string intValRefTempAer;
// intValRefTempSol = ValRefTempSol.Text;
// intValRefTempAer = ValRefTempAer.Text;
// ProiectSera.App_Code.GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text);
GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text);
}
}
}

Your GlobalClass is in the namespace ProiectSera.App_Code.
So the class name is ProiectSera.App_Code.GlobalClass
Make sure you don't have a ProiectSera class in the ProiectSera namespace also, otherwise if declaring using ProiectSera on top, it'll try to use it (as a general rule, don't name any class the same as your namespace).
If that still doesn't work, you may want to try using the global namespace:
global::ProiectSera.GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text);
and see if that works: if it doesn't, and GlobalClass is in the same project, then there's something else you haven't shown us
Update
The only other thing that comes to mind, if you are positive that both files are on the same project/assembly, is that GlobalClass.cs is not being actually compiled. Make sure the Build Action is set to Compile (you can see the build action right clicking on the GlobalClass.cs in the solution explorer and selecting Properties).

If you are using VS.NET:
Right click on the References folder on your project.
Select Add Reference.
Select the .NET tab (or select the Browse button if it is not a .NET Framework assembly).
Double-click the assembly containing the namespace in the error message.
Press the OK button.

Ensure the following...
That you have a project reference to ProiectSera from your web application, if it's in a separate library. If GlobalClass is in the web application project itself, you won't require this, but if GlobalClass is defined in a separate library in the same solution or elsewhere, then you're going to need to add a reference to that external library in your web application.
Ensure that ProiectSera should not be ProjectSera (if it's a typo).
Ensure that you have your ProiectSera using statement in place at the top (using ProiectSera;). Assuming that this is the correct namespace. Check the namespace of your GlobalClass class and use that using accordingly in the class that wishes to use its functionality.
Then, simply call this in your code, assuming that Update is a static method of GlobalClass.
GlobalClass.Update(ValRefTempSol.Text, ValRefTempAer.Text);
EDIT: given that you've now posted your GlobalClass code, you can see that the namespace for this class is ProiectSera.App_Code;. So you need to have that as your using statement in the other class using ProiectSera.App_Code;. And then call it via simply GlobalClass.Update, as mentioned above.
If you don't understand how namespacing works in C#, then I recommend you check this out (https://msdn.microsoft.com/en-us/library/dfb3cx8s.aspx).

Cannot find the namespace for generic type "List"

I have a strange error and don't know how to solve that. I have a Form which gets opened by another (Main)Form. When I write
List<String> valStoreAsString = new List<String>();
I get "The value or namespace List could not get found". My using directives are the following:
using System;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Collections;
using System.Runtime.InteropServices;
In the other Forms it works fine. What happened here?

Add following using directive to the list of usings.
using System.Collections.Generic;
Tip
If you are using Visual Studio and if you don't know the namespace then type name of type (Case sensetive) in editor and then press ctrl+ . and select add using option and VS will add related using for you.
or you can right click on name of Type and select Resolve option and select using .... sub option.

c# ProcessMemoryReaderLib not working

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using ProcessMemoryReaderLib;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
This seems to always return the error
"Error 1 The type or namespace name 'ProcessMemoryReaderLib' could not be found (are you missing a using directive or an assembly reference?) C:\Users\giacomo\documents\visual studio 2010\Projects\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs 10 7 WindowsFormsApplication1
"

In your Solution Explorer, right click your References > Add Reference then click Browse, then find and select your .dll File and add it to your references. You can't include a library in your project with using if you don't include your assembly.
Take a look at here for more details: http://msdn.microsoft.com/en-us/library/wkze6zky.aspx

Just build the project after adding the reference of the ProcessMemoryReaderLib.dll in your project,then use using ProcessMemoryReaderLib; in your class file

C# Blocking IP by modifying Windows 7 Firewall

I'm starting to build an anti-ddos application in C#, it's going to block IP's by checking how many connections there are, in an amount of time, but I can't find whats needed for NetFwMgrType.
Here's code, I just started:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using NETCONLib;
using NATUPNPLib;
using NetFwTypeLib;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
Type NetFwMgrType = Type.GetTypeFromProgID("HNetCfg.FwMgr", false);
INetFwMgr mgr = (INetFwMgr)Activator.CreateInstance(NetFwMgrType);
bool Firewallenabled = mgr.LocalPolicy.CurrentProfile.FirewallEnabled;
public Form1()
{
InitializeComponent();
}
}
}
The errors I get is:
Error 1 A field initializer cannot reference the non-static field, method, or property 'WindowsFormsApplication1.Form1.NetFwMgrType'
Error 2 A field initializer cannot reference the non-static field, method, or property 'WindowsFormsApplication1.Form1.mgr'
(I added references: \Windows\System32\hnetcfg.dll and \Windows\System32\FireWallAPI.dll)
Thanks for answer.
Oh and if you know how to block IPs with Firewall modifying, as well, it would save me a lot of googling:)

Determining labels from another partial class/windows form

I'm bit new at this so excuse me if my question is a bit novice. I'm designing a Windows form application to basically replace an old excel spreadsheet then email system(not that its much of a system). After the forms are filled out the answers are saved in terms of public variables, which is fine since it's a small program. Im having trouble referencing my variable from another windows form. Basically, I would like to have the filled out form close and a new "review" window pop up. I'm just using labels that will be show what the value of the variable is. If it was in the same class it wouldn't be a problem but im using two different forms that are partial classes of the same namespace. A bit of code:
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace OPS_PictureLoader
{
public partial class Points_Screen : Form
{
public int DevJobStandardsTotal = 0;
And the label I would like to show a "0"(or whatever the program has added to it)
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace OPS_PictureLoader
{
public partial class Review : Form
{
public Review()
{
InitializeComponent();
label14.Text = DevJobStandardsTotal;
Again, thanks and feel free to tell me Im totally wrong :D

You need to pass the instance of the first form to the second form's constructor:
public Review(Points_Screen owner)
{
InitializeComponent();
label14.Text = owner.DevJobStandardsTotal;