VB/VB.NET 禁止一个程序运行多次

VB.NET 禁止一个程序运行多次代码:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
If UBound(Diagnostics.Process.GetProcessesByName(Diagnostics.Process.GetCurrentProcess.ProcessName)) > 0 Then
MsgBox("当前程序已运行,请结束进程后重新打开！", vbOKOnly, "提示")
Me.Close()
End If
End Sub
''''''''''''''''''''''''''''''''''''
'程序代码部分
'.................
'
'''''''''''''''''''''''''''''''''''
End Class
VB禁止一个程序运行多次代码:
Private Sub Form_Load()
If App.PrevInstance Then
MsgBox "当前程序已运行,请结束进程后重新打开！", vbOKOnly, "提示"
End If
End Sub
''''''''''''''''''''''''''''''''''''
'程序代码部分
'.................
'
'''''''''''''''''''''''''''''''''''