GridPrinter: Extend dbgrid2 demo for filtered dataset.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@9446 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/gridprinter/examples/dbgrid2/dbgrid_demo.lpi

@@ -15,7 +15,6 @@
       <XPManifest>
         <DpiAware Value="True"/>
       </XPManifest>
-      <Icon Value="0"/>
     </General>
     <BuildModes Count="1">
       <Item1 Name="Default" Default="True"/>

components/gridprinter/examples/dbgrid2/main.lfm

@@ -6,8 +6,8 @@ object Form1: TForm1
   Caption = 'Form1'
   ClientHeight = 382
   ClientWidth = 689
+  LCLVersion = '3.99.0.0'
   OnCreate = FormCreate
-  LCLVersion = '2.3.0.0'
   object DBGrid1: TDBGrid
     Left = 0
     Height = 345
@@ -42,8 +42,8 @@ object Form1: TForm1
       AutoSize = True
       BorderSpacing.Around = 6
       Caption = 'Print preview...'
-      OnClick = Button1Click
       TabOrder = 0
+      OnClick = Button1Click
     end
     object cbShowTitles: TCheckBox
       AnchorSideLeft.Control = Button1
@@ -56,8 +56,8 @@ object Form1: TForm1
       Width = 75
       BorderSpacing.Around = 6
       Caption = 'Show titles'
-      OnChange = cbShowTitlesChange
       TabOrder = 1
+      OnChange = cbShowTitlesChange
     end
     object cbShowIndicator: TCheckBox
       AnchorSideLeft.Control = cbShowTitles
@@ -71,8 +71,22 @@ object Form1: TForm1
       BorderSpacing.Left = 6
       BorderSpacing.Around = 6
       Caption = 'Show indicator column'
-      OnChange = cbShowIndicatorChange
       TabOrder = 2
+      OnChange = cbShowIndicatorChange
+    end
+    object cbFiltered: TCheckBox
+      AnchorSideLeft.Control = cbShowIndicator
+      AnchorSideLeft.Side = asrBottom
+      AnchorSideTop.Control = cbShowIndicator
+      AnchorSideTop.Side = asrCenter
+      Left = 350
+      Height = 19
+      Top = 9
+      Width = 296
+      BorderSpacing.Left = 6
+      Caption = 'Print only records with IntFields >=1000 and <= 2000'
+      TabOrder = 3
+      OnChange = cbFilteredChange
     end
   end
   object DataSource1: TDataSource
@@ -99,6 +113,7 @@ object Form1: TForm1
   end
   object BufDataset1: TBufDataset
     FieldDefs = <>
+    OnFilterRecord = BufDataset1FilterRecord
     Left = 167
     Top = 64
   end

components/gridprinter/examples/dbgrid2/main.pas

@@ -17,14 +17,17 @@ type
     Button1: TButton;
     cbShowTitles: TCheckBox;
     cbShowIndicator: TCheckBox;
+    cbFiltered: TCheckBox;
     DataSource1: TDataSource;
     DBGrid1: TDBGrid;
     GridPrinter1: TGridPrinter;
     GridPrintPreviewDialog1: TGridPrintPreviewDialog;
     Panel1: TPanel;
+    procedure BufDataset1FilterRecord(DataSet: TDataSet; var Accept: Boolean);
     procedure Button1Click(Sender: TObject);
     procedure cbShowIndicatorChange(Sender: TObject);
     procedure cbShowTitlesChange(Sender: TObject);
+    procedure cbFilteredChange(Sender: TObject);
     procedure FormCreate(Sender: TObject);
     procedure GridPrinter1AfterPrint(Sender: TObject);
     procedure GridPrinter1GetCellText(Sender: TObject; AGrid: TCustomGrid;
@@ -132,6 +135,15 @@ begin
   end;
 end;
 
+procedure TForm1.BufDataset1FilterRecord(DataSet: TDataSet; var Accept: Boolean
+  );
+var
+  value: Integer;
+begin
+  value := Dataset.FieldByName('IntField').AsInteger;
+  Accept := (value >= 1000) and (value <= 2000);
+end;
+
 procedure TForm1.cbShowIndicatorChange(Sender: TObject);
 begin
   if cbShowIndicator.Checked then
@@ -148,6 +160,19 @@ begin
     DBGrid1.Options := DBGrid1.Options - [dgTitles];
 end;
 
+procedure TForm1.cbFilteredChange(Sender: TObject);
+begin
+  if cbFiltered.Checked then
+  begin
+    BufDataset1.OnFilterRecord := @BufDataset1FilterRecord;
+    BufDataset1.Filtered := true;
+  end else
+  begin
+    BufDataset1.Filtered := false;
+    BufDataset1.OnFilterRecord := nil;
+  end;
+end;
+
 { The OnGetCellText fires whenever a cell is printed and the printer needs to
   know the cell text. }
 procedure TForm1.GridPrinter1GetCellText(Sender: TObject; AGrid: TCustomGrid;
@@ -181,13 +206,35 @@ begin
 end;
 
 { Since the DBGrid does not load all records, but we want to print all
-  of them, we must tell the printer the real number of rows to print. }
+  of them, we must tell the printer the real number of rows to print.
+  Note that depending on the type of dataset RecordCount may be wrong,
+  in particular when the dataset is filtered.}
 procedure TForm1.GridPrinter1GetRowCount(Sender: TObject; AGrid: TCustomGrid;
   var ARowCount: Integer);
+var
+  accept: Boolean;
+  n: Integer;
 begin
-  BufDataset1.Last;
-  BufDataset1.First;
-  ARowCount := BufDataset1.RecordCount;
+  if BufDataset1.Filtered then
+  begin
+    BufDataset1.DisableControls;
+    BufDataset1.First;
+    n := 0;
+    while not BufDataset1.EoF do
+    begin
+      BufDataset1FilterRecord(BufDataset1, accept);
+      if accept then inc(n);
+      BufDataset1.Next;
+    end;
+    BufDataset1.First;
+    BufDataset1.EnableControls;
+  end else
+  begin
+    BufDataset1.Last;
+    BufDataset1.First;
+    n := BufDataset1.RecordCount;
+  end;
+  ARowCount := n;
   if dgTitles in TDBGrid(AGrid).Options then
     inc(ARowCount);    // added 1 for the header row
 end;