将使用 inpout32.dll 的 Visual Basic 并行端口应用程序转换为 Delphi

Question

我得到了这个简单的 VB 应用程序和库，我被告知可以打开连接到 0x378 基地址的打印机端口的门/turnstyle。

   'Inp and Out declarations for port I/O using inpout32.dll.

Public Declare Function Inp Lib "inpout32.dll" Alias "Inp32" _
    (ByVal PortAddress As Integer) _
    As Integer

Public Declare Sub Out Lib "inpout32.dll" Alias "Out32" _
    (ByVal PortAddress As Integer, _
    ByVal Value As Integer)

------------------------------------------------------------------------------------
Option Explicit
Dim Value As Integer
Dim PortAddress As Integer

Private Sub cmdWriteToPort_Click()
'Write to a port.
Out PortAddress, Value
'Read back and display the result.
Text1.Text = Inp(PortAddress)
Value = Value + 1
If Value = 255 Then Value = 0
End Sub

Private Sub Form_Load()
'Test program for inpout32.dll
Value = 0
'Change PortAddress to match the port address to write to:
'(Usual parallel-port addresses are &h378, &h278, &h3BC)
PortAddress = &H378
End Sub

但是我需要在 Delphi 5 中重新编写它以集成到我的应用程序中。

1. 是否可以通过 D5 访问同一个库？
2. 使用以下代码，我的方向是否正确？

//使用库的端口 I/O 的 Inp 和 Out 声明

function Inp(PortAddress:String); external 'inpout32.dll.dll'
begin
 return ??
end;

procedure Output(PortAddress:String;Value:Integer); external 'inpout32.dll.dll'

procedure TForm1.FormActivate(Sender: TObject);
begin
//Test program for inpout32.dll

Value := 0;

//Change PortAddress to match the port address to write to:
//(Usual parallel-port addresses are &h378, &h278, &h3BC)

PortAddress := '&H378';
end;

procedure TForm1.Button1Click(Sender: TObject);
begin

//Write to a port.
Output(PortAddress, Value);

//Read back and display the result.
Edit1.Text := Inp(PortAddress);
Value := Value + 1;

if Value = 255 then
Value := 0;

end;

我不确定如何声明库函数以及将变量声明为什么（&H378 显然不是整数）

谢谢

Answer 1

PortAddress 被声明为整数，所以不要使用字符串。您的代码应如下所示：

//Inp and Out declarations for port I/O using inpout32.dll.
function Inp(PortAddress: Integer): Integer; stdcall; external 'inpout32.dll' name 'Inp32';

procedure Output(PortAddress, Value: Integer); stdcall; external 'inpout32.dll' name 'Out32';

procedure TForm1.FormActivate(Sender: TObject);
begin
  //Test program for inpout32.dll
  Value := 0;

  //Change PortAddress to match the port address to write to:
  //(Usual parallel-port addresses are $378, $278, $3BC)
  PortAddress := $378;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  //Write to a port.
  Output(PortAddress, Value);

  //Read back and display the result.
  Edit1.Text := IntToStr(Inp(PortAddress));
  Value := Value + 1;

  if Value = 255 then
    Value := 0;
end;

Answer 2

您应该完全放弃使用 inpout32.dll，因为它仅用于直接访问打印机端口并且使您的代码转换复杂化。使用ZLOPRTIO Delphi 库，您可以更高效地完成同样的工作。