A error when trying to run a simple program to get global key+mouseclick

See more:

C#

I get the following error when trying to run the program:
Could not load type 'Program' from assembly 'keypressed, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' because the method 'mouse_event' has no implementation (no RVA).

it's a program to catch a global key pressed, and if F2 is pressed it clicks unlimited until it is pressed again.

using System;
using System.Diagnostics;
using System.Windows.Forms;
using System.Threading;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

class Program
{
    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;
    private static LowLevelKeyboardProc _proc = HookCallback;
    private static IntPtr _hookID = IntPtr.Zero;
    public static Boolean Click = false;

    public static extern void mouse_event(int dwFlags, int dx, int dy, int cButtons, int dwExtraInfo);



    public const int MOUSEEVENTF_LEFTDOWN = 0x02;
    public const int MOUSEEVENTF_LEFTUP = 0x04;
    public const int MOUSEEVENTF_RIGHTDOWN = 0x08;
    public const int MOUSEEVENTF_RIGHTUP = 0x10;

    public static void MouseClick()
    {
        int x = 100;
        int y = 100;

        mouse_event(MOUSEEVENTF_LEFTDOWN, x, y, 0, 0);
        mouse_event(MOUSEEVENTF_LEFTUP, x, y, 0, 0);
    }

    public static void doclick()
    {
        while (true)
            if (Click)
                MouseClick();
    }


    public static void Main()
    {

        Thread t = new Thread(new ThreadStart(doclick));
        t.Start();
        _hookID = SetHook(_proc);
        Application.Run();
        UnhookWindowsHookEx(_hookID);
 
    }

    private static IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    private delegate IntPtr LowLevelKeyboardProc(
        int nCode, IntPtr wParam, IntPtr lParam);

    private static IntPtr HookCallback(
        int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        {
            int vkCode = Marshal.ReadInt32(lParam);
            Console.WriteLine((Keys)vkCode);
            if (vkCode == 113)
                if (Click) Click = false;
                else Click = true;

        }
        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int idHook,
        LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool UnhookWindowsHookEx(IntPtr hhk);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
        IntPtr wParam, IntPtr lParam);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
}

I tested them separetly, the mouse click(it works ok), and to get the global key pressed;