How to use extension classes

Questions & Answers
1

I have a class that I am using as my extension:

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public static class Extensions {
    /// <summary>
/// Converts a list to a string
/// </summary>
    public static string ConvertToString(this List<object> list)
    {
        var output = string.Empty;
        foreach (var item in list)
        {
            output += item.ToString() + ",";
        }
        return output;
    }
	
}

This is inside a folder called General Scripts.

In another folder called GUI Scripts I have a class that is trying to access this class.

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class Cube_GesturePreference : MonoBehaviour {
    string[] gestureOptions = {   Cube_DemoPhase.selection.ConvertToString(),
                                  Cube_DemoPhase.selection.ConvertToString(),
                                  Cube_DemoPhase.selection.ConvertToString()
                              }; 
    public void Start(){}
    public void Update(){}

}

But it gives me this error:

Error	2	Instance argument: cannot convert from 'System.Collections.Generic.List<string>' to 'System.Collections.Generic.List<object>'
Error	1	'System.Collections.Generic.List<string>' does not contain a definition for 'ConvertToString' and the best extension method overload 'Extensions.ConvertToString(System.Collections.Generic.List<object>)' has some invalid arguments

Can anyone help me figure out why my extension method is not showing up when I try to access it?

3

Does this work?

public static string ConvertToString<T>(this List<T> list)
2

Looks like Cube_DemoPhase.selection is of type List but the extension method is for List. Just change that to

public static string ConvertToString(this List<string> list)