I want to use App.config for storing some setting.
I tried to use the next code for getting a parameter from a config file.

```cs
private string GetSettingValue(string paramName)
{
    return String.Format(ConfigurationManager.AppSettings[paramName]);
}

```

I also added `System.Configuration` for it (I used a separate class), and in App.config file I have:

```xml
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup> 
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <appSettings>
    <add key ="key1" value ="Sample" />
  </appSettings>
</configuration>

```

But I got an error while trying to use `ConfigurationManager` - `ConfigurationManager can't exist in such context`, but I already added `System.Configuration`. Or did I miss something?

**EDIT**:

class with config (full view)

```cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;

namespace browser
{
    class ConfigFile
    {
        private string GetSettingValue(string paramName)
        {
            return String.Format(ConfigurationManager.AppSettings[paramName]);
        }
    }
}

```

**EDIT2**

Add how it looks

![enter image description here](https://i.stack.imgur.com/BN0Tq.png)

This means the problem is not during using `ConfigurationManger` but before - the program "says" that it "doesn't know such element" as I understand the error - the "Element ConfigurationManager" doesn't exist in such context"

**EDIT3**

![enter image description here](https://i.stack.imgur.com/rjG9K.png)

**EDIT 4**

![enter image description here](https://i.stack.imgur.com/mUiJq.png)