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Delphi's ParamStr and ParamCount functions are designed to help operate the parameters (command-line arguments) passed to the application.

Due to the way ParamStr function is implemented in Delphi, parameters passed using double quotes ("") will not be parsed correctly (quotes will be removed).

The "CmdLineHelper" unit provides 3 custom Delphi functions to overcome the problem of the RTL's ParamStr implementation.

1. //original code author: Remy Lebeau (TeamB)
   
2. unit CmdLineHelper;
   
3. 
   
4. interface
   
5. 
   
6. uses windows;
   
7. 
   
8. //command line parameters + program path
   
9. function GetCommandLine: string;
   
10. //number of parameters
    
11. function GetParamCount: Integer;
    
12. //parameter by index
    
13. function GetParamStr(Index: Integer): String;
    
14. 
    
15. implementation
    
16. 
    
17. function GetCommandLine : string;
    
18. begin
    
19.   result := windows.GetCommandLine;
    
20. end;
    
21. 
    
22. function GetNextParam(var CmdLine: PChar; Buffer: PChar; Len: PInteger): Boolean;
    
23. var
    
24.   InQuotedStr, IsOdd: Boolean;
    
25.   NumSlashes, NewLen, cnt: Integer;
    
26. begin
    
27.   Result := False;
    
28.   if Len <> nil then Len^ := 0;
    
29.   if CmdLine = nil then Exit;
    
30.   while (CmdLine^ <= ' ') and (CmdLine^ <> #0) do CmdLine := CharNext(CmdLine) ;
    
31.   if CmdLine^ = #0 then Exit;
    
32.   InQuotedStr := False;
    
33.   NewLen := 0;
    
34.   repeat
    
35.     if CmdLine^ = '\' then
    
36.     begin
    
37.       NumSlashes := 0;
    
38.       repeat
    
39.         Inc(NumSlashes) ;
    
40.         CmdLine := CharNext(CmdLine) ;
    
41.       until CmdLine^ <> '\';
    
42.       if CmdLine^ = '"' then
    
43.       begin
    
44.         IsOdd := (NumSlashes mod 2) <> 0;
    
45.         NumSlashes := NumSlashes div 2;
    
46.         Inc(NewLen, NumSlashes) ;
    
47.         if IsOdd then Inc(NewLen) ;
    
48.         if Buffer <> nil then
    
49.         begin
    
50.           for cnt := 0 to NumSlashes-1 do
    
51.           begin
    
52.             Buffer^ := '\';
    
53.             Inc(Buffer) ;
    
54.           end;
    
55.           if IsOdd then
    
56.           begin
    
57.             Buffer^ := '"';
    
58.             Inc(Buffer) ;
    
59.           end;
    
60.         end;
    
61.         if IsOdd then CmdLine := CharNext(CmdLine) ;
    
62.       end else
    
63.       begin
    
64.         Inc(NewLen, NumSlashes) ;
    
65.         if Buffer <> nil then
    
66.         begin
    
67.           for cnt := 0 to NumSlashes-1 do
    
68.           begin
    
69.             Buffer^ := '\';
    
70.             Inc(Buffer) ;
    
71.           end;
    
72.         end;
    
73.       end;
    
74.       Continue;
    
75.     end;
    
76.     if CmdLine^ <> '"' then
    
77.     begin
    
78.       if (CmdLine^ <= ' ') and (not InQuotedStr) then Break;
    
79.       Inc(NewLen) ;
    
80.       if Buffer <> nil then
    
81.       begin
    
82.         Buffer^ := CmdLine^;
    
83.         Inc(Buffer) ;
    
84.       end;
    
85.     end
    
86.     else
    
87.       InQuotedStr := not InQuotedStr;
    
88.     CmdLine := CharNext(CmdLine) ;
    
89.   until CmdLine^ = #0;
    
90.   if Len <> nil then Len^ := NewLen;
    
91.   Result := True;
    
92. end;
    
93. 
    
94. function GetParamCount: Integer;
    
95. var
    
96.   CmdLine: PChar;
    
97. begin
    
98.   Result := 0;
    
99.   CmdLine := windows.GetCommandLine;
    
100.   GetNextParam(CmdLine, nil, nil) ;
     
101.   while GetNextParam(CmdLine, nil, nil) do Inc(Result) ;
     
102. end;
     
103. 
     
104. function GetParamStr(Index: Integer): String;
     
105. var
     
106.   Buffer: array[0..MAX_PATH] of Char;
     
107.   CmdLine, P: PChar;
     
108.   Len: Integer;
     
109. begin
     
110.   Result := '';
     
111.   if Index <= 0 then
     
112.   begin
     
113.     Len := GetModuleFileName(0, Buffer, MAX_PATH+1) ;
     
114.     SetString(Result, Buffer, Len) ;
     
115.   end else
     
116.   begin
     
117.     CmdLine := windows.GetCommandLine;
     
118.     GetNextParam(CmdLine, nil, nil) ;
     
119.     repeat
     
120.       Dec(Index) ;
     
121.       if Index = 0 then Break;
     
122.       if not GetNextParam(CmdLine, nil, nil) then Exit;
     
123.     until False;
     
124.     P := CmdLine;
     
125.     if GetNextParam(P, nil, @Len) then
     
126.     begin
     
127.       SetLength(Result, Len) ;
     
128.       GetNextParam(CmdLine, PChar(Result), nil) ;
     
129.     end;
     
130.   end;
     
131. end;
     
132. 
     
133. end.

複製代碼

Note: for testing, you can pass the parameter from the IDE under Run-Parameters menu option.

The screen shot displays the output when the application is called using:

/about delphi "programming" 123.45 67,89
Drop a TMemo ("Memo1") on a Delphi form. Here's a sample usage of the "CmdLineHelper" unit:

1. uses CmdLineHelper;
   
2. ...
   
3. var
   
4.   idx : integer;
   
5. begin
   
6.   with Memo1.Lines do
   
7.   begin
   
8.     Clear;
   
9. 
   
10.     Add('CMD Line: ' + CmdLineHelper.GetCommandLine + #13#10) ;
    
11.     Add('Number of params: ' + IntToStr(CmdLineHelper.GetParamCount) + #13#10) ;
    
12. 
    
13.     for idx := 1 to CmdLineHelper.GetParamCount do
    
14.     begin
    
15.       Memo1.Lines.Add(CmdLineHelper.GetParamStr(idx)) ;
    
16.     end;
    
17.   end;
    
18. end;

複製代碼

參考來源 http://delphi.about.com/od/delphitips2007/qt/parse_cmd_line.htm