VB6中如何防止系统休眠？（博问出现问题，在些先编辑好以做备份）

以下VB6代码无效：

Option Explicit

Private Enum Execution_State
    ES_SYSTEM_REQUIRED = &H1
    ES_DISPLAY_REQUIRED = &H2
    ES_USER_PRESENT = &H4
    ES_CONTINUOUS = &H80000000
End Enum

Private Declare Sub SetThreadExecutionState Lib "kernel32" (ByRef esFlags As Long)

Private Sub Form_Load()
    SetThreadExecutionState Execution_State.ES_SYSTEM_REQUIRED Or Execution_State.ES_DISPLAY_REQUIRED Or Execution_State.ES_CONTINUOUS
End Sub

但以下C#代码却非常管用：

public partial class Form1 : Form
    {
        [DllImport("kernel32.dll")]
        static extern uint SetThreadExecutionState(uint esFlags);
        const uint ES_SYSTEM_REQUIRED = 0x00000001;
        const uint ES_DISPLAY_REQUIRED = 0x00000002;
        const uint ES_CONTINUOUS = 0x80000000;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SetThreadExecutionState(ES_CONTINUOUS | ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED);
        }
    }

哪位知道原因，还望不吝赐教。