BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Re: Object reference not set to an instance of an object          BorlandTalk.com Forum Index -> comp.lang.pascal.delphi.misc View previous topic :: View next topic   Author Message Tom de Neef Guest Posted: Mon Jan 24, 2005 12:14 am    Post subject: Re: Object reference not set to an instance of an object "Danny" <dc (AT) mbox303 (DOT) swipnet.se> schreef in bericht news:jiWId.16326$Of5.11294 (AT) nntpserver (DOT) swip.net... Quote: Hi! I have a really annoying problem. It's from a program I've done in Delphi 5 but now tries to get it working in Delphi 8. I have reproduced the problem in the following extremly simple program, it has something to do with the StretchDraw routine. When i run the program and execute the event (formclick) an error occours: "Object reference not set to an instance of an object" Anyone have any ideas what to do. I have spent many hours on the internet trying to solve that problem, this is my last chance except installing Delphi 5 again. Thanks Daniel ------- The source code for the program that reproduces the error ------ unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls; type TForm1 = class(TForm) procedure FormClick(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.nfm} procedure TForm1.FormClick(Sender: TObject); var n:integer; bild:TPicture; begin bild.LoadFromFile('c:testbild.jpg'); Form1.Canvas.StretchDraw(TRect.Create(1,1,100,150), bild.Graphic); bild.Free; end; end. Bild has not been created when you try loading from file. Insert a bild.create before the loadFromFile. The debugger will highlight the line following the one in which the error occured. Tom Back to top AlanGLLoyd Guest Posted: Mon Jan 24, 2005 7:22 am    Post subject: Re: Object reference not set to an instance of an object In article <jiWId.16326$Of5.11294 (AT) nntpserver (DOT) swip.net>, "Danny" <dc (AT) mbox303 (DOT) swipnet.se> writes: Quote: I have reproduced the problem in the following extremly simple program, it has something to do with the StretchDraw routine. That's where it surfaces, but your problem is that Bild is a variable holding a reference (ie a place to store an actual occurence) of an object. For such a non-automatially ceated object, _you_ must create the object. When you call Create on an object it returns a reference to that object which you must place in the variable. Place ... Bild := TPicture.Create; .... before your call to load the file. As _you_ have created the object, then _you_ must free it - and this you have done. Alan Lloyd [email]alanglloyd (AT) aol (DOT) com[/email] Back to top Danny Guest Posted: Mon Jan 24, 2005 10:53 am    Post subject: Re: Object reference not set to an instance of an object ....ok, interesting reading! I thought I've done something wrong with StretchDraw. Well, now it works when I created it. Thanks! "AlanGLLoyd" <alanglloyd (AT) aol (DOT) com> wrote Quote: In article <jiWId.16326$Of5.11294 (AT) nntpserver (DOT) swip.net>, "Danny" [email]dc (AT) mbox303 (DOT) swipnet.se[/email]> writes: I have reproduced the problem in the following extremly simple program, it has something to do with the StretchDraw routine. That's where it surfaces, but your problem is that Bild is a variable holding a reference (ie a place to store an actual occurence) of an object. For such a non-automatially ceated object, _you_ must create the object. When you call Create on an object it returns a reference to that object which you must place in the variable. Place ... Bild := TPicture.Create; ... before your call to load the file. As _you_ have created the object, then _you_ must free it - and this you have done. Alan Lloyd [email]alanglloyd (AT) aol (DOT) com[/email] Back to top Danny Guest Posted: Mon Jan 24, 2005 2:07 pm    Post subject: Re: Object reference not set to an instance of an object I'm sorry to bother you again. But now I have implemented the code in my actual project, and it doesn't work. It seems to be another problem now. But the same error dialog appears. I have tried some different things and the problem seems to be in the picture loading or something. I have now put the whole code from my actual project into this testprogram, I can't understand what's causing the problem, I might try some other way of printing the pictures. unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, System.ComponentModel, Printers; type TForm1 = class(TForm) PrintDialog1: TPrintDialog; procedure FormClick(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.nfm} procedure TForm1.FormClick(Sender: TObject); var cw, // canvas.width ch, // canvas.height rx, // räknare för kolumn (x-axel) ry, // räknare för rad (y-axel) b, // bildnummer p, // sidnummer x1,x2,y1,y2 // bildens koordinater :integer; bild: TBitmap; namn: String; begin PrintDialog1.Execute; With Printer Do Begin Title:=('Utskrift'); cw := PageWidth; ch := PageHeight; rx:=1; ry:=1; p:=1; BeginDoc; Canvas.Brush.Style:=bsClear; Canvas.Font.Height:=Round(ch/50); Canvas.Font.Color:=clBlack; Canvas.TextOut(Round(cw/20),Round(ch/40),'Testskolan, testklass'); Canvas.Font.Height:=Round(ch/90); For b:=0 To 10 Do Begin bild := TBitmap.Create; bild.LoadFromFile('c:testport.jpg'); namn := 'testnamn'; x1 := Round( cw/20 + (cw/5.3*(rx-1)) ); x2 := Round( x1 + (cw/6.7) ); y1 := Round( ch/15 + (ch/5.5*(ry-1)) ); y2 := Round( y1 + ((x2-x1)*1.25) ); Canvas.StretchDraw(TRect.Create(x1,y1,x2,y2),bild); Canvas.Rectangle(TRect.Create(x1,y1,x2,y2)); bild.Free; If Length(namn)<24 Then Canvas.TextOut(x1, Round(y1+(ch/7.3)), namn) Else Begin If Length(namn)>48 Then Delete(namn,49,length(namn)); Canvas.TextOut(x1, Round(y1+(ch/7.10)), Copy(namn,0,24)); Canvas.TextOut(x1, Round(y1+(ch/6.45)), Copy(namn,25,Length(namn))); End; If rx=5 Then Begin Inc(ry); rx:=1; End Else Inc(rx); If ry=6 Then Begin Canvas.Font.Height:=Round(ch/80); Canvas.Textout(Round(cw-(cw/11.4)), Round(ch-(ch/27)), 'Sida '+IntToStr(p)); Printer.NewPage; Inc(p); Canvas.Textout(Round(cw-(cw/11.4)), Round(ch-(ch/27)), 'Sida '+IntToStr(p)); ry:=1; Canvas.Font.Height:=Round(ch/90); End; End; EndDoc; End; end; end. Back to top Tom de Neef Guest Posted: Mon Jan 24, 2005 2:39 pm    Post subject: Re: Object reference not set to an instance of an object Comments in the code ... Tom "Danny" <dc (AT) mbox303 (DOT) swipnet.se> schreef in bericht news:Zi7Jd.16475$Of5.11284 (AT) nntpserver (DOT) swip.net... Quote: unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, System.ComponentModel, Printers; type TForm1 = class(TForm) PrintDialog1: TPrintDialog; procedure FormClick(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.nfm} procedure TForm1.FormClick(Sender: TObject); var cw, // canvas.width ch, // canvas.height rx, // räknare för kolumn (x-axel) ry, // räknare för rad (y-axel) b, // bildnummer p, // sidnummer x1,x2,y1,y2 // bildens koordinater :integer; bild: TBitmap; namn: String; begin PrintDialog1.Execute; With Printer Do Begin Title:=('Utskrift'); cw := PageWidth; ch := PageHeight; rx:=1; ry:=1; p:=1; BeginDoc; Canvas.Brush.Style:=bsClear; Canvas.Font.Height:=Round(ch/50); Canvas.Font.Color:=clBlack; Canvas.TextOut(Round(cw/20),Round(ch/40),'Testskolan, testklass'); Canvas.Font.Height:=Round(ch/90); For b:=0 To 10 Do Begin bild := TBitmap.Create; // You could move the create outside the loop bild.LoadFromFile('c:testport.jpg'); // Can a Tbitmap load a JPG ? namn := 'testnamn'; x1 := Round( cw/20 + (cw/5.3*(rx-1)) ); x2 := Round( x1 + (cw/6.7) ); y1 := Round( ch/15 + (ch/5.5*(ry-1)) ); y2 := Round( y1 + ((x2-x1)*1.25) ); // Canvas.StretchDraw(TRect.Create(x1,y1,x2,y2),bild); // Canvas.Rectangle(TRect.Create(x1,y1,x2,y2)); Canvas.StretchDraw(Rect(x1,y1,x2,y2),bild); // check out Rect function Canvas.Rectangle(Rect(x1,y1,x2,y2)); Quote: bild.Free; // and move the free outside the loop as well If Length(namn)<24 Then Canvas.TextOut(x1, Round(y1+(ch/7.3)), namn) Else Begin // If Length(namn)>48 Then Delete(namn,49,length(namn)); If Length(namn)>48 Then SetLength(namn,49); // Canvas.TextOut(x1, Round(y1+(ch/7.10)), Copy(namn,0,24)); Canvas.TextOut(x1, Round(y1+(ch/7.10)), Copy(namn,1,24)); // 1-based string Quote: Canvas.TextOut(x1, Round(y1+(ch/6.45)), // Copy(namn,25,Length(namn))); Copy(namn,26,maxInt)); Quote: End; If rx=5 Then Begin Inc(ry); rx:=1; End Else Inc(rx); If ry=6 Then Begin Canvas.Font.Height:=Round(ch/80); Canvas.Textout(Round(cw-(cw/11.4)), Round(ch-(ch/27)), 'Sida '+IntToStr(p)); Printer.NewPage; // You're still in 'with printer do', so NewPage suffices Inc(p); Canvas.Textout(Round(cw-(cw/11.4)), Round(ch-(ch/27)), 'Sida '+IntToStr(p)); ry:=1; Canvas.Font.Height:=Round(ch/90); End; End // of for b loop EndDoc; End; end; end. Back to top Danny Guest Posted: Mon Jan 24, 2005 4:25 pm    Post subject: Re: Object reference not set to an instance of an object Hi and thanks for the look... but it's still the same error (as in the subject, "object reference"). About your comments: - Yes in Delphi 8 you can a jpg in a TBitmap. - The StretchDraw(TRect.Create... must bu used, because it's different from early Delphi where you could use Rect only. - From the beginning I had bild.create/free outside the loop, thought that it was better myself, that was a new testcode. - The other changes where interesting, I'll try those. Thanks "Tom de Neef" <tdeneef (AT) qolor (DOT) nl> wrote Quote: Comments in the code ... Tom Back to top ronenbitman@gmail.com Guest Posted: Tue Jan 25, 2005 9:34 am    Post subject: Re: Object reference not set to an instance of an object Danny Firstly in Delphi when you create an object you should do it this way (this way your sure it will be freed even if there is an error on the way) bild := TBitmap.Create try For b := .... Begin .... .... Bild.LoadFromFile.... .... .... End; Finally Bild.Free; End; that should probably fix it? Hope i helped Back to top VBDis Guest Posted: Tue Jan 25, 2005 10:19 am    Post subject: Re: Object reference not set to an instance of an object Im Artikel <jiWId.16326$Of5.11294 (AT) nntpserver (DOT) swip.net>, "Danny" <dc (AT) mbox303 (DOT) swipnet.se> schreibt: Quote: "Object reference not set to an instance of an object" Did you use "with" in your code? Then remove it and try again... DoDi Back to top Danny Guest Posted: Tue Jan 25, 2005 11:15 am    Post subject: Re: Object reference not set to an instance of an object ....mkay... that was a kinda good clue... I'll try... Quote: Danny Firstly in Delphi when you create an object you should do it this way (this way your sure it will be freed even if there is an error on the way) bild := TBitmap.Create try For b := .... Begin ... ... Bild.LoadFromFile.... ... ... End; Finally Bild.Free; End; that should probably fix it? Hope i helped Back to top Danny Guest Posted: Tue Jan 25, 2005 1:41 pm    Post subject: Re: Object reference not set to an instance of an object ....yes I did... Now I have tried to remove "with" (With Printer Do...) and put "Printer." before all print-commands instead, but the problem remains... "VBDis" <vbdis (AT) aol (DOT) com> wrote Quote: Im Artikel <jiWId.16326$Of5.11294 (AT) nntpserver (DOT) swip.net>, "Danny" [email]dc (AT) mbox303 (DOT) swipnet.se[/email]> schreibt: "Object reference not set to an instance of an object" Did you use "with" in your code? Then remove it and try again... DoDi Back to top Danny Guest Posted: Tue Jan 25, 2005 1:51 pm    Post subject: Re: Object reference not set to an instance of an object Now I have tried that too. Actually, now it creates a document when I run the print routine (the code here). But the document is empty without pictures and text, but before it didn't even create a document, just a printer error message (a log file from acrobat in my case). So I guess it's might be a good idea with try-finally, I'll put it in my code now which I'm developing in Delphi 7 (where it works. as you might now, the problem started when I went from D5 to D. Thanks anyway /Daniel <ronenbitman (AT) gmail (DOT) com> wrote Quote: Danny Firstly in Delphi when you create an object you should do it this way (this way your sure it will be freed even if there is an error on the way) bild := TBitmap.Create try For b := .... Begin ... ... Bild.LoadFromFile.... ... ... End; Finally Bild.Free; End; that should probably fix it? Hope i helped Back to top Jamie Guest Posted: Tue Jan 25, 2005 8:25 pm    Post subject: Re: Object reference not set to an instance of an object Danny wrote: Quote: Now I have tried that too. Actually, now it creates a document when I run the print routine (the code here). But the document is empty without pictures and text, but before it didn't even create a document, just a printer error message (a log file from acrobat in my case). So I guess it's might be a good idea with try-finally, I'll put it in my code now which I'm developing in Delphi 7 (where it works. as you might now, the problem started when I went from D5 to D. Thanks anyway /Daniel [email]ronenbitman (AT) gmail (DOT) com[/email]> wrote in message news:1106645689.135499.238540 (AT) c13g2000cwb (DOT) googlegroups.com... Danny, in some cases there are printers that will not work very well when usng a DDB bitmap. they need a DIB at 24 bits. just before you get ready to send the image to the printer code try this. theBitmap.pixelform := pf24bit; Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> comp.lang.pascal.delphi.misc All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.