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Delphi L07 Controls at Runtime P1

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Delphi L07 Controls at Runtime P1

  1. 1. Intro to Event-driven Programming and Forms with Delphi L07 - Creating Controls at Runtime Part 1 Mohammad Shaker mohammadshakergtr.wordpress.com Intro to Event-driven Programming and Forms with Delphi @ZGTRShaker 2010, 2011, 2012
  2. 2. Creating Controls at Runtime • Let’s have the following form design
  3. 3. Creating Controls at Runtime •We declare the “control” like any other variable var i: Integer; var TempShape:TShape; procedure TForm2.Button1Click(Sender: TObject); begin // Now we initialize the shape to use it as a NORMAL // one TempShape:= TShape.Create(self); End;
  4. 4. Creating Controls at Runtime • Compiler Error – Tshape is undeclared type • So don’t forget to add ExtCtrls. uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls;
  5. 5. Creating Controls at Runtime •Compile and Run but no shape outputted after writing the following code. – What’s messing? Var TempShape:Tshape; procedure TForm2.Button1Click(Sender: TObject); begin // Now we initialize the shape to use it as a NORMAL // one TempShape:= Tshape.Create(self); End;
  6. 6. Creating Controls at Runtime procedure TForm2.Button1Click(Sender: TObject); begin TempShape:= Tshape.Create(self); TempShape.Parent:= Panel1; end;
  7. 7. Creating Controls at Runtime procedure TForm2.Button1Click(Sender: TObject); begin TempShape:= Tshape.Create(self); TempShape.Parent:= Panel1; TempShape.Shape:= stEllipse; TempShape.Height:= 100; TempShape.Width:= 50; TempShape.Left:= 100; TempShape.Top:= 50; TempShape.Brush.Color:= 255; end;
  8. 8. Creating Controls at Runtime
  9. 9. Creating Controls at Runtime • Let’s have the following form design
  10. 10. Creating Controls at Runtime procedure TForm2.Button1Click(Sender: TObject); var i: integer; ShapeArr: Array [1..5] of TShape; begin for i:= 1 to 5 do Begin ShapeArr[i]:= TShape.Create(self); ShapeArr[i].Parent:= Panel1; ShapeArr[i].Brush.Color:= i*100; ShapeArr[i].Left:= 100; ShapeArr[i].Top:= i*40; End; end;
  11. 11. Creating Controls at Runtime
  12. 12. Creating Controls at Runtime
  13. 13. Creating Controls at Runtime var ButtonPtr: ^TButton; procedure TForm2.Button1Click(Sender: TObject); var i: integer; begin for i:= 1 to StrToInt(Edit1.Text) do Begin new(ButtonPtr); ButtonPtr^:= TButton.Create(self); ButtonPtr^.Parent:= Panel1; ButtonPtr^.Left:= 100; ButtonPtr^.Top:= i*40; End; end;
  14. 14. Creating Controls at Runtime
  15. 15. Creating Controls at Runtime procedure TForm2.Button1Click(Sender: TObject); var i: integer; myButton: ^TButton; begin for i:= 1 to StrToInt(Edit1.Text) do Begin new(ButtonPtr); ButtonPtr^:= TButton.Create(self); ButtonPtr^.Caption:= 'Button' + IntToStr(i); ButtonPtr^.Parent:= Panel1; ButtonPtr^.Left:= 100; ButtonPtr^.Top:= i*40; End; end;
  16. 16. Creating Controls at Runtime
  17. 17. Creating Controls at Runtime Type TempPtr = ^ TForm; TempArr = array [1..Cst] of TempPtr; Var Arr:TempArr; procedure TForm1.Button1Click(Sender: TObject); Var i:integer; begin for i:=1 to Cst do Begin new(Arr[i]); // as he have said we need to New the ptr Arr[i]^:= TForm.Create(self); Arr[i]^.Show();// Now in every count a new form will be // created and showed End; End;
  18. 18. Creating Controls at Runtime
  19. 19. Creating Controls at Runtime Type TempPtr = ^ TForm; TempArr = array [1..Cst] of TempPtr; Var Arr:TempArr; procedure TForm1.Button1Click(Sender: TObject); Var i:integer; begin for i:=1 to Cst do Begin // new(Arr[i]); Arr[i]^:= TForm.Create(self); Arr[i]^.Show();// Now in every count a new form will be // created and showed End; End;
  20. 20. Creating Controls at Runtime
  21. 21. Creating Controls at Runtime Type PtrTemp=^Rcd; Rcd=record ShapePtr:^Tshape; Next:PtrTemp; end; Var ls,s,Cruiser:PtrTemp; // we assume that we have the procedure INSERT already
  22. 22. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Timer1Timer(Sender: TObject); Begin new(s); new(s^.ShapePtr); s^.ShapePtr^:= TShape.Create(self); s^.ShapePtr^.Parent:= Panel1; s^.ShapePtr^.Show(); s^.ShapePtr^.width:=10; insert(ls,s); end;
  23. 23. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Timer1Timer(Sender: TObject); Begin new(s); insert(ls,s); new(s^.ShapePtr); s^.ShapePtr^:= TShape.Create(self); s^.ShapePtr^.Parent:= Panel1; s^.ShapePtr^.Show(); s^.ShapePtr^.width:=10; End;
  24. 24. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Button1Click(Sender: TObject); Begin Cruiser:=ls; While (Cruiser<>nil) do begin Cruiser^.ShapePtr:= Shape1; // Compile Errorincompatible types Cruiser:= Cruiser^.Next; end; end;
  25. 25. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Button1Click(Sender: TObject); Begin new(Cruiser); Cruiser:=ls; While Cruiser<>nil do begin Cruiser^.ShapePtr^:= Shape1; Cruiser:= Cruiser^.Next; end; end; // This will result in all the list (ShapePtr) pointers to be pointing to the static shape(Shape1).
  26. 26. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Button1Click(Sender: TObject); Begin new(Cruiser); Cruiser:=ls; While Cruiser<>nil do begin Cruiser^.ShapePtr^:= Button1; Cruiser:= Cruiser^.Next; end; end; // Compiler Error. incompatible types // TButton and Tshape are different from each other
  27. 27. Creating Controls at Runtime // we assume that we have the procedure INSERT already procedure TForm1.Button1Click(Sender: TObject); Begin new(Cruiser); Cruiser:=ls; While Cruiser<>nil do begin Cruiser^.ShapePtr^.Width:= Cruiser^.ShapePtr^.Width+10; Cruiser:= Cruiser^.Next; end; end; // This will result in increase of the width of all // shapes of the list by 10 Cool
  28. 28. To be continued..
  29. 29. See you!

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