[Amin_Mansouri]

Instructions: This one is simple, call the method, check the results. Add reference to this Namespace:

using System.Runtime.InteropServices;
using System.ComponentModel;

کد:

//Namespace reference
using System.Runtime.InteropServices;

/// <summary>
/// enum to hold the recycle
/// bin flags
/// </summary>
enum RecycleFlags : uint
{
    SHERB_NOCONFIRMATION = 0x00000001,
    SHERB_NOPROGRESSUI = 0x00000002,
    SHERB_NOSOUND = 0x00000004
}

/// <summary>
/// Import Win32 DLL for emptying the recycle bin
/// </summary>
/// <param name="hwnd"></param>
/// <param name="pszRootPath"></param>
/// <param name="dwFlags"></param>
/// <returns></returns>
[DllImport("Shell32.dll", CharSet = CharSet.Unicode)]
static extern uint SHEmptyRecycleBin(IntPtr hwnd,string pszRootPath,RecycleFlags dwFlags);

public bool EmptyRecycleBin()
{
    try
    {
        uint result = SHEmptyRecycleBin(IntPtr.Zero, null, RecycleFlags.SHERB_NOSOUND | RecycleFlags.SHERB_NOCONFIRMATION);

        if (result > 0)
            return true;
        else
            throw new Win32Exception(Marshal.GetLastWin32Error());
    }
    catch (Exception ex)
    {
        this._message = string.Format("Error emptying Recycle Bin: {0}", ex.Message);
        return false;
    }
}