我尝试着写了一段，但是卸载段存在问题，请指点！

[Files]
Source: ISTask.dll; DestDir: {app}; Flags: ignoreversion

[Code]
function RunTask(FileName: string; bFullpath: Boolean): Boolean;
external 'RunTask@files:ISTask.dll stdcall delayload';

function KillTask(ExeFileName: string): Integer;
external 'KillTask@files:ISTask.dll stdcall delayload';

function InitializeSetup(): Boolean;
begin
Result:= true;
  if RunTask('MyProg.exe', false) then
  begin
    if
MsgBox('安装程序检测到 MyProg.exe 正在运行！'#13''#13'单击“是”按钮关闭 LockOn
程序；'#13''#13'单击“否”按钮进行强制安装！', mbConfirmation, MB_YESNO) = IDYES then
      KillTask('MyProg.exe');
  end
end;

function InitializeUninstall(): Boolean;
begin
Result:= true;
  if RunTask('MyProg.exe', false) then
  begin
    if
MsgBox('安装程序检测到 MyProg.exe 正在运行！'#13''#13'单击“是”按钮关闭 LockOn
程序；'#13''#13'单击“否”按钮进行强制安装！', mbConfirmation, MB_YESNO) = IDYES then
      KillTask('MyProg.exe');
  end
end;

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用上面的代码，在卸载时判断进程的dll已经没有了，所以不能调用它的函数。其实安装和卸载时调用的dll是不同的。

这样修改代码应该可以：

[Files]
Source: ISTask.dll; DestDir: {app}; Flags: ignoreversion

[Code]
function RunTask1(FileName: string; bFullpath: Boolean): Boolean;
external 'RunTask@files:ISTask.dll stdcall delayload';

function KillTask1(ExeFileName: string): Integer;
external 'KillTask@files:ISTask.dll stdcall delayload';

function RunTask(FileName: string; bFullpath: Boolean): Boolean;
external 'RunTask@{app}\ISTask.dll stdcall uninstallonly';

function KillTask(ExeFileName: string): Integer;
external 'KillTask@{app}\ISTask.dll stdcall uninstallonly';

function InitializeSetup(): Boolean;
begin
Result:= true;
  if RunTask1('MyProg.exe', false) then
  begin
    if
MsgBox('安装程序检测到 MyProg.exe 正在运行！'#13''#13'单击“是”按钮关闭 LockOn
程序；'#13''#13'单击“否”按钮进行强制安装！', mbConfirmation, MB_YESNO) = IDYES then
      KillTask1('MyProg.exe');
  end
end;

function InitializeUninstall(): Boolean;
begin
Result:= true;
  if RunTask('MyProg.exe', false) then
  begin
    if
MsgBox('安装程序检测到 MyProg.exe 正在运行！'#13''#13'单击“是”按钮关闭 LockOn
程序；'#13''#13'单击“否”按钮进行强制安装！', mbConfirmation, MB_YESNO) = IDYES then
      KillTask('MyProg.exe');
    UnloadDll(ExpandConstant('{app}\ISTask.dll'));
  end
end;