Author: Erwin Molendijk

How to change the mousecursor into a hourglass/normal.

Answer:

1   unit waitcursor;
2   { WaitCursor  -  Copyright (c) 2001 by E.J.Molendijk
3   
4     A mousecursor hourglass/normal changer tool. Supports layered requests.
5   
6     WCursor.SetWait     = mouse cursor as Hourglass
7     WCursor.SetWaitSQL  = mouse cursor as SQL Hourglass
8     WCursor.SetNormal   = mouse cursor as normal
9   
10    example:
11        WCursor.setWait;
12        try
13          DoSometingVerySlow;
14        finally
15          WCursor.setNormal;
16        end;
17  }
18  
19  interface
20  
21  type
22    TWaitCursor = class
23    private
24      FCursor: integer;
25      FCnt: integer;
26    public
27      constructor Create;
28      destructor Destroy; override;
29      procedure SetCursor(Index: integer);
30      procedure SetWait;
31      procedure SetWaitSQL;
32      procedure SetNormal;
33    end;
34  
35  var
36    WCursor: TWaitCursor;
37  
38  implementation
39  
40  uses Forms, Controls;
41  
42  constructor TWaitCursor.Create;
43  begin
44    inherited;
45    // depth is zero
46    FCnt := 0;
47  
48    // remember default cursor
49    FCursor := Screen.Cursor;
50  end;
51  
52  destructor TWaitCursor.Destroy;
53  begin
54    // Reset to default cursor
55    Screen.Cursor := FCursor;
56    inherited;
57  end;
58  
59  procedure TWaitCursor.SetCursor(Index: integer);
60  begin
61    // select cursor
62    Screen.Cursor := Index;
63  end;
64  
65  procedure TWaitCursor.SetNormal;
66  begin
67    // decrease depth
68    if FCnt > 0 then
69      Dec(FCnt);
70  
71    // if we reach depth 0 we restore default cursor
72    if FCnt = 0 then
73      SetCursor(FCursor);
74  end;
75  
76  procedure TWaitCursor.SetWait;
77  begin
78    // increase depth
79    Inc(FCnt);
80  
81    // select wait cursor
82    SetCursor(crHourglass);
83  end;
84  
85  procedure TWaitCursor.SetWaitSQL;
86  begin
87    // increase depth
88    Inc(FCnt);
89  
90    // select wait cursor
91    SetCursor(crSQLWait);
92  end;
93  
94  initialization
95    WCursor := TWaitCursor.Create;
96  finalization
97    WCursor.Free;
98  end.