1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
{
fpGUI - Free Pascal GUI Library
Copyright (C) 2006 - 2007 See the file AUTHORS.txt, included in this
distribution, for details of the copyright.
See the file COPYING.modifiedLGPL, included in this distribution,
for details about redistributing fpGUI.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Description:
Database support classes. This serves as an example of how someone
could implement DB aware components for fpGUI.
}
unit fpgui_db;
{$mode objfpc}{$H+}
// If enabled it outputs debug information for this unit
{.$Define DEBUG}
interface
uses
Classes,
db,
gfx_widget,
gui_label{, gui_edit};
type
TfpgFieldDataLink = class(TDataLink)
private
FWidget: TfpgWidget;
FField: TField;
FFieldName: string;
FOnDataChange: TNotifyEvent;
function GetCanModify: Boolean;
procedure SetFieldName(const AFieldName: string);
procedure UpdateField;
protected
procedure ActiveChanged; override;
procedure RecordChanged(AField: TField); override;
public
constructor Create(AWidget: TfpgWidget);
property CanModify: Boolean read GetCanModify;
property Field: TField read FField;
property FieldName: string read FFieldName write SetFieldName;
property Widget: TfpgWidget read FWidget write FWidget;
property OnDataChange: TNotifyEvent read FOnDataChange write FOnDataChange;
end;
TfpgDBLabel = class(TfpgCustomLabel)
private
FDataLink: TfpgFieldDataLink;
function GetDataField: String;
function GetField: TField;
procedure SetDataField(const ADataField: String);
function GetDataSource: TDataSource;
procedure SetDataSource(ADataSource: TDataSource);
procedure DataChange(Sender: TObject);
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property Field: TField read GetField;
published
property DataField: string read GetDataField write SetDataField;
property DataSource: TDataSource read GetDataSource write SetDataSource;
property Enabled;
property BackgroundColor;
property Color;
property FontDesc;
property Text;
end;
{
// TfpgEdit needs to be refactor some more first!!
TfpgDBEdit = class(TfpgCustomEdit)
private
FDataLink: TfpgFieldDataLink;
function GetDataField: string;
function GetDataSource: TDataSource;
function GetField: TField;
function GetReadOnly: Boolean;
procedure SetDataField(const ADataField: string);
procedure SetDataSource(const ADataSource: TDataSource);
procedure DataChange(Sender: TObject);
procedure SetReadOnly(const AValue: Boolean);
protected
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
property Field: TField read GetField;
published
property DataField: string read GetDataField write SetDataField;
property DataSource: TDataSource read GetDataSource write SetDataSource;
property Enabled;
property BackgroundColor;
property Color;
property FontDesc;
property Text;
property ReadOnly: Boolean read GetReadOnly write SetReadOnly default False;
end;
}
implementation
{ TfpgFieldDataLink }
function TfpgFieldDataLink.GetCanModify: Boolean;
begin
Result := not ReadOnly and (Field <> nil) and Field.CanModify;
end;
procedure TfpgFieldDataLink.SetFieldName(const AFieldName: string);
begin
if AFieldName <> FieldName then
begin
FFieldName := AFieldName;
UpdateField;
end;
end;
procedure TfpgFieldDataLink.UpdateField;
begin
{$IFDEF DEBUG} WriteLn('## UpdateField. DataSet: ', DataSource.DataSet.ClassName); {$ENDIF}
FField := DataSource.DataSet.FindField(FieldName);
if Assigned(OnDataChange) then
OnDataChange(Self);
end;
procedure TfpgFieldDataLink.ActiveChanged;
begin
inherited ActiveChanged;
UpdateField;
end;
procedure TfpgFieldDataLink.RecordChanged(AField: TField);
begin
inherited RecordChanged(AField);
if Assigned(OnDataChange) then
OnDataChange(Self);
end;
constructor TfpgFieldDataLink.Create(AWidget: TfpgWidget);
begin
inherited Create;
FWidget := AWidget;
end;
{ TfpgDBLabel }
function TfpgDBLabel.GetDataField: String;
begin
Result := FDataLink.FieldName;
end;
function TfpgDBLabel.GetField: TField;
begin
Result := FDataLink.Field;
end;
procedure TfpgDBLabel.SetDataField(const ADataField: String);
begin
FDataLink.FieldName := ADataField;
end;
function TfpgDBLabel.GetDataSource: TDataSource;
begin
Result := FDataLink.DataSource;
end;
procedure TfpgDBLabel.SetDataSource(ADataSource: TDataSource);
begin
FDataLink.DataSource := ADataSource;
end;
procedure TfpgDBLabel.DataChange(Sender: TObject);
begin
{$IFDEF DEBUG} Write(Classname + '.DataChange'); {$ENDIF}
if Assigned(FDataLink.Field) then
begin
Text := FDataLink.Field.DisplayText;
{$IFDEF DEBUG} WriteLn(' new text: "', Text, '"'); {$ENDIF}
end
else
begin
Text := '';
{$IFDEF DEBUG} WriteLn('DataLink has no data'); {$ENDIF}
end;
end;
constructor TfpgDBLabel.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FDataLink := TfpgFieldDataLink.Create(Self);
FDataLink.OnDataChange := @DataChange;
end;
destructor TfpgDBLabel.Destroy;
begin
FDataLink.Free;
inherited Destroy;
end;
end.
|
