This question already has an answer here:
Resource not found error when using TForm as base for a component
(1 answer)
Closed 6 years ago.
I have put together this code for creating a dynamic form
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
type
TForm2 = class(TForm)
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form2: TForm2;
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
a:TForm2;
begin
a:=TForm2.Create(nil);
end;
end.
I get an error saying resource tform2 cannot be found. What must i do?
Thanks
You are calling the TForm.Create() constructor that loads the TForm contents from a DFM, but your project does not have a DFM for TForm2, which is why you are getting the resource error. To skip that, you need to use the TForm.CreateNew() constructor instead.
procedure TForm1.Button1Click(Sender: TObject);
var
a: TForm2;
begin
a := TForm2.CreateNew(nil, 0);
...
end;
In Delphi you must declare only one form per unit, also each form needs a dfm file, that file store the form definition and components properties. In your code you have this error because the application can't found the dfm file for the TForm2 form. So to fix the problem just create a new form (TForm2) in a separate unit and then add the unit a name to the unit where you need to call the TForm2.
Related
I have a major problem and I have no idea how it might be corrected. Out of the blue, when I compile then try to run my application - which I have been working on for six months - I get a Class Not Registered error. I also have a pop-up error message saying that dbx.dbl was not found. I have added nothing to the program in the past few days which included any new classes. I am using Delphi 5. I do not know how to identify which class is not registered. The program will not run and I have spent hours trying to track down the problem without success.
More information: I have moved the executable and data files to another computer, and it all runs fine. So it seems to be a problem with my development box.
More Information: I did as fpiette suggested but found nothing which helped. So I created a very basic application:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, Db, ADODB;
type
TForm1 = class(TForm)
ADOConnection1: TADOConnection;
ADOQuery1: TADOQuery;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
begin
ADOConnection1.Connected := True;
ADOQuery1.Close;
ADOQuery1.Connection := ADOConnection1;
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add('select * from tblsupplier');
ADOQuery1.Open;
end;
end.
The Class Not Registered error occurs when it executes the ADOQuery1.Open; line.
Am I right in assuming that since there are no other components in the program that the error must be in the ADO code? The ADOConnection1 points at an Access database called Suppliers and the connection test was successful.
I have a simple project in Delphi:
program Project1;
uses
Forms,
Unit2 in 'Unit2.pas',
Unit1 in 'Unit1.pas' {Form1};
{$R *.res}
begin
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.
Unit1:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
uses Unit2;
{$R *.dfm}
function encodeData(var Data:array of Byte; var Size: Integer): Integer;
var
i: Intger
begin
...
for i := 1 to Size do
begin
Data[i] := Data[i] + unit2.SomeArray[i]
end;
...
Result := 0;
Exit;
end
...
The second unit:
unit Unit2;
interface
implementation
const
SomeArray:Array [0..65000] of LongWord = (
...
);
end.
When I'm trying to build this project I get errors like this:
[Error] Unit1.pas(41): Undeclared identifier: 'SomeArray'
What's wrong with this code? I checked Delphi wiki and other questions and didn't find solution for this issue...
You need to define SomeArray in the interface section of the unit. Currently, you have it in the implementation section, which is purposely hidden from other units. Only things defined/declared in the interface are visible to other units.
In the documentation you linked, it's described:
The implementation section of a unit begins with the reserved word implementation and continues until the beginning of the initialization section or, if there is no initialization section, until the end of the unit. The implementation section defines procedures and functions that are declared in the interface section. Within the implementation section, these procedures and functions may be defined and called in any order. You can omit parameter lists from public procedure and function headings when you define them in the implementation section; but if you include a parameter list, it must match the declaration in the interface section exactly.
In addition to definitions of public procedures and functions, the implementation section can declare constants, types (including classes), variables, procedures, and functions that are private to the unit. That is, unlike the interface section, entities declared in the implementation section are inaccessible to other units.
(Emphasis mine)
I've downloaded Delphi XE7 and having some problems with accessing another Units...
I need to call procedures from another units, so I'll give a very basic illustration, simple program...
This is code from main Unit1 with form and button1:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics,
Controls, Forms, Dialogs, StdCtrls, Unit2;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
ShowMessage('Hello');
end;
end.
And this is the code from Unit2:
unit Unit2;
interface
implementation
uses Unit1;
end.
Now, how is it possible to make procedure Button1Click like in Unit2 to showmessage let's say HelloFromUnit2 when button1 on form1 is clicked? Unit2 is codeUnit without anything..
Use the build in procedure for calling the Click handler
Leave form 1 the way it is:
unit Unit2;
interface
implementation
uses
Unit1;
procedure Click;
begin
if Assigned(Form1) then
Form1.Button1.Click;
end;
end.
Add a procedure declaration to the public section of TForm1, like this
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
public
Procedure SayHello;
end;
...
procedure TForm1.SayHello;
begin
ShowMessage('Hello');
end;
end.
Then in Unit2 you would call this procedure. You would have to ensure that Form2 has already been instantiated - or create a new instance for your call.
Do not use this mechanism for event handlers!
The header of your post doesn't match the question in the text
"Call Button1Click in Form1/Unit1 from Unit2" vs.
"Now, how is it possible to make procedure Button1Click like in Unit2 to showmessage let's say HelloFromUnit2 when button1 on form1 is clicked?"
I answer the question in the text (as I understand it). If this is not what you intended, you might want to rephrase the question in the text.
Add, to Form1.Button1Click, a call to a new procedure in unit2
procedure TForm1.Button1Click(Sender: TObject);
begin
ShowMessage('Hello');
SayHelloFromUnit2; // <---- add this
end;
In unit2 add the following to the interface section:
procedure SayHelloFromUnit2;
and to the implementation section
uses Vcl.Dialogs;
procedure SayHelloFromUnit2;
begin
ShowMessage('Hello from unit2');
end;
I have an object that is created on Form1 and I would like to be able to access one of its fields on Form2. I have tried to google it and nobody can give an answer that I can understand. Please excuse me but I am a novice.
Form1
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
Ttest=class
public
sName:string;
end;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
uses Unit2;
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
myObj:Ttest;
begin
myObj.Create;
myObj.sName := 'Name';
Form2.Show;
end;
end.
Form2
unit Unit2;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm2 = class(TForm)
Button2: TButton;
procedure Button2Click(Sender: TObject);
end;
var
Form2: TForm2;
implementation
uses Unit1;
{$R *.dfm}
procedure TForm2.Button2Click(Sender: TObject);
begin
ShowMessage(myObj.sName);//This is not working
end;
end.
You have two forms that both use an object. You should define the object in a separate unit and list it in the Uses clause in the Interface section of both forms. Try using something already defined in a main library, like TStringlist, so you don't get confused with this part.
From what you're showing here, you're attempting to create an instance of that object in one form and do something with it in another form. That's a common thing to do: you may have one unit that asks for a filename and loads a file into a TStringList, then hands that over to another form or unit to deal with.
The way you're doing it, however, can be improved to reduce coupling between the two forms.
What you want to do is define a property like this in TForm2:
TForm2 = class( TForm )
. . .
private
Ftestobj : TTest; // or TStringlist
public
property testobj : TTest read Ftestobj write Ftestobj;
Then in TForm1.OnButtonClick do something like this:
form2.testobj := myobj;
form2.Show;
And then this becomes:
procedure TForm2.Button2Click(Sender: TObject);
begin
ShowMessage(Ftestobj.sName);
end;
I did a whole session in CodeRage 9 on this topic recently, in fact. It's entitled, "Have you embraced your inner plumber yet?" and it's all about moving data in and out of forms like this. (I call it plumbing code.)
Search for "coderage 9" and watch the video. At the end is a link where you can download my example code. That should keep you busy for a while. :)
I did it by creating OLE object with Delphi in 2000/NT/XP as following:
Voice := CreateOLEObject('SAPI.SpVoice');
Voice.speak(...)
But this does not work in Vista, how can I make my program simply speak some text in Vista?
I just tried (D2009 on Vista Home Premium) with the following code and it works!
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComObj;
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
Voice: Variant;
begin
Voice := CreateOLEObject('SAPI.SpVoice');
Voice.speak('Hello World');
end;
end.
FYI, there is a nice paper on using speech in Delphi programming by Brian Long...
(Very) Late Update:
For why it might not work in Vista and give an EZeroDivide exception outside the IDE, see this other SO question: Delphi SAPI Text-To-Speech