Creating Reports with Delphi and ADO - Defining the Layout
(Page 4 of 4 )
We still have to define the layout of the report. So, click on the rsys component and then go to the object inspectors events tab. Scroll down to the Onprint event and double click on it. Add the following code:
procedure TForm1.rsysPrint(Sender: TObject);
begin
with Sender as TBaseReport do begin
NewLine;
SetFont('Arial',18);
FontColor := clRed;
Print('Welcome to Code Based Reporting in Rave');
NewLine;
NewLine;
ClearTabs;
SetTab(0.2, pjLeft, 0.4, 0, 0, 0);
SetTab(0.4, pjRight, 2.1, 0, 0, 0);
SetTab(2.1, pjRight, 3.0, 0, 0, 0);
SetTab(3.0, pjRight, 4.0, 0, 0, 0);
SetFont('Arial', 10);
Bold := True;
PrintTab('Name');
PrintTab('Surname');
PrintTab('Age');
PrintTab('Occupation');
Bold := False;
NewLine;
q1.Open;
q1.first;
while not q1.Eof do begin
Printtab(q1.FieldByName('name').Text);
Printtab(q1.FieldByName('surname').Text);
Printtab(q1.FieldByName('age').Text);
Printtab(q1.FieldByName('occupation').Text);
newline;
q1.Next;
if (LinesLeft < 3) and (not q1.Eof) then begin
NewPage;
end;
end;
end;
end;
This function basically prints a title and headers, and then the retrieved results. Lets start from the top. The first four lines deal with formatting and displaying the title of the report. The "Newline" phrase creates a space between whatever is on top and below. The "setTab" procedure does exactly what it says, it sets the positions of the text in the report. Here's how the procedure is declared in Delphi:
procedure SetTab(NewPos: double; NewJustify: TPrintJustify;
NewWidth: double; NewMargin: double; NewLines: byte; NewShade:
byte);
NewPos defines the starting position of the tab. If NewPos is set to the constant NA, then the tab will start immediately after the previous tab box.
NewJustify defines whether the tab is left (pjLeft), right (pjRight) or center (pjCenter) justified. If a non-zero width is given, then a tab box is defined and the text will be justified within the tab box rather than justified at the tab position.
NewMargin defines the distance between the tab box side and the text in hundredths of an inch.
NewLines uses the BoxLineXxxx constants to define where lines are to be drawn around the tab box.
NewShade defines the percentage of background shading to use for this tab box.
Before the "while" loop, the "PrintTab" procedure is used to print the headers for the report. Within the while loop, "PrintTab" creates dynamic text that prints out the results from the query. There is also a check that is made with in the loop:
if (LinesLeft < 3) and (not q1.Eof) then begin
NewPage;
end;
This check is placed there to make sure that a new page is created when the end of the page is reached. The "LinesLeft" function will count the number of lines left on the page; if it is less then three lines, a new page is created.
Here's a result of this code:
Formatting the report
You can format the report even further to make it look more professional. For example you can set the background colors and a border. You can also use a more professional looking font, or make various other little changes. The possibilities are endless. Just keep in mind that the more formatting you want, the more code you need to add to make it happen. With a report that is Designer- based, you will not need to write a lot of code, and will therefore be able to do a lot more, much more quickly. But it has its downsides, which we will discuss in detail when I get around to writing the next article about Rave Reporting.
Conclusion
I have not gone into great detail about the Visual Designer, as it is a entire topic in itself, but what I've shown in this article should be enough for those of you who want to use Rave reports with ADO. At some point I will write an article specifically relating to Rave Report Visual Designer.
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