Author: Jonas Bilinkevicius

How to disable the functionality of a TForm to move

Answer:

Solve 1:

1   unit FreezeForm;
2   
3   interface
4   
5   uses
6     Windows, Messages, Classes, Graphics, Forms, Controls, Buttons,
7     StdCtrls, ExtCtrls;
8   
9   type
10    TFrmFreeze = class(TForm)
11      BtnValidate: TBitBtn;
12      BtnSave: TBitBtn;
13      BtnPreview: TBitBtn;
14      BtnPrint: TBitBtn;
15      BtnExit: TBitBtn;
16      BtnHelp: TBitBtn;
17      procedure BtnExitClick(Sender: TObject);
18    private
19      FOldWindowProc: TWndMethod; {Old WindowProc}
20      {Window subclassing methods}
21      procedure HookForm;
22      procedure UnhookForm;
23      procedure WndProcForm(var AMsg: TMessage);
24    protected
25      procedure CreateWnd; override;
26    public
27      destructor Destroy; override;
28    end;
29  
30  var
31    FrmFreeze: TFrmFreeze;
32  
33  implementation
34  
35  {$R *.DFM}
36  
37  procedure TFrmFreeze.CreateWnd;
38  begin
39    inherited;
40    if csDesigning in ComponentState then
41      Exit; {Don't need to hook when designing}
42    if Enabled then
43    begin
44      HookForm; {Hook the main form's Window}
45    end;
46  end;
47  
48  procedure TFrmFreeze.HookForm;
49  begin
50    if csDesigning in ComponentState then
51      Exit;
52    FOldWindowProc := WindowProc;
53    WindowProc := WndProcForm;
54  end;
55  
56  procedure TFrmFreeze.UnhookForm;
57  begin
58    if csDesigning in ComponentState then
59      Exit;
60    {If we are "hooked" then undo what Hookform did}
61    if Assigned(FOldWindowProc) then
62    begin
63      if HandleAllocated then
64      begin
65        WindowProc := FOldWindowProc;
66      end;
67      FOldWindowProc := nil;
68    end;
69  end;
70  
71  {WndProcForm is our replacement for our WindowProc. We grab any Windows messages
72  that we need here}
73  
74  procedure TFrmFreeze.WndProcForm(var AMsg: TMessage);
75  var
76    cmdType: Word;
77  begin
78    if Enabled then
79    begin
80      case AMsg.Msg of
81        WM_SYSCOMMAND:
82          begin
83            cmdType := AMsg.WParam and $FFF0;
84            case cmdType of
85              SC_MINIMIZE, SC_MAXIMIZE, SC_MOVE, SC_SIZE:
86                Exit;
87            end;
88          end;
89        WM_GETMINMAXINFO:
90          Exit;
91      end;
92    end;
93    {Call the default windows procedure}
94    FOldWindowProc(AMsg);
95  end;
96  
97  destructor TFrmFreeze.Destroy;
98  begin
99    if not (csDesigning in ComponentState) then
100     UnhookForm; {Stop interfering ...}
101   inherited Destroy;
102 end;
103 
104 procedure TFrmFreeze.BtnExitClick(Sender: TObject);
105 begin
106   Close;
107 end;
108 
109 end.



Solve 2:
110 
111 procedure TCoolHint2KForm.WMNCHitTest(var message: TWMNCHitTest);
112 begin
113   inherited;
114   if message.Result = htCaption then
115     message.Result := htNowhere;
116 end;