WPS的VBA代码中如何添加判断语句，如果已经有一个进程在运行RTD函数，就不再开启新的进程来运行RTD函数。这样可以避免RTD服务断开的问题。

你可以使用Windows API函数来获取当前正在运行的进程列表，并且判断是否存在已经运行的RTD进程。以下是一个简单的示例代码：

Option Explicit

Private Declare Function CreateToolhelp32Snapshot Lib "kernel32" (ByVal dwFlags As Long, ByVal th32ProcessID As Long) As Long
Private Declare Function Process32First Lib "kernel32" (ByVal hSnapshot As Long, lppe As PROCESSENTRY32) As Long
Private Declare Function Process32Next Lib "kernel32" (ByVal hSnapshot As Long, lppe As PROCESSENTRY32) As Long
Private Declare Sub CloseHandle Lib "kernel32" (ByVal hObject As Long)

Private Const TH32CS_SNAPPROCESS As Long = 2

Private Type PROCESSENTRY32
  dwSize As Long
  cntUsage As Long
  th32ProcessID As Long
  th32DefaultHeapID As Long
  th32ModuleID As Long
  cntThreads As Long
  th32ParentProcessID As Long
  pcPriClassBase As Long
  dwFlags As Long
  szExeFile As String * 260
End Type

Private Function IsRtdProcessRunning() As Boolean
  Dim hProcessSnap As Long
  Dim uProcess As PROCESSENTRY32
  Dim bFound As Boolean
  
  hProcessSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)
  If hProcessSnap = -1 Then Exit Function
  
  uProcess.dwSize = Len(uProcess)
  bFound = Process32First(hProcessSnap, uProcess)
  Do While bFound
    If InStr(uProcess.szExeFile, "Excel.exe") > 0 And InStr(uProcess.szExeFile, "RTDServer") > 0 Then
      IsRtdProcessRunning = True
      Exit Do
    End If
    bFound = Process32Next(hProcessSnap, uProcess)
  Loop
  
  CloseHandle hProcessSnap
End Function

你可以在调用RTD函数之前，先调用`IsRtdProcessRunning`函数来判断是否已经有一个RTD进程在运行，如果是的话就不再开启新的进程。