Class TRadioGroup not found error.

[timw4mail]

I've been following along with the "Learn to program using Lazarus" book. I'm working on the Polymorphic drawing example, and it seems to compile fine. But when the program is run, I get an EClassNotFound exception, saying that the TRadioGroup class is not found.

As far as I can see, I am including the correct Unit, but the exception trace seems to go deep into the LCL. I've tried the same code on mac OS, mac OS X PPC, and Windows 10.

Is there something simple I'm missing? I've attached the relevant code.

[timw4mail]

Since I can't attach the .lfm file, here it is:

Code: Pascal  [Select][+][-]

1. object Form1: TForm1
2.   Left = 627
3.   Height = 240
4.   Top = 322
5.   Width = 320
6.   Caption = 'Polymorphic drawing example'
7.   ClientHeight = 240
8.   ClientWidth = 320
9.   OnCreate = FormCreate
10.   LCLVersion = '2.0.12.0'
11.   object rgShape: TRadioGroup
12.     Left = 41
13.     Height = 68
14.     Top = 141
15.     Width = 239
16.     AutoFill = True
17.     Caption = 'Type of FDrawing'
18.     ChildSizing.LeftRightSpacing = 6
19.     ChildSizing.EnlargeHorizontal = crsHomogenousChildResize
20.     ChildSizing.EnlargeVertical = crsHomogenousChildResize
21.     ChildSizing.ShrinkHorizontal = crsScaleChilds
22.     ChildSizing.ShrinkVertical = crsScaleChilds
23.     ChildSizing.Layout = cclLeftToRightThenTopToBottom
24.     ChildSizing.ControlsPerLine = 1
25.     ClientHeight = 49
26.     ClientWidth = 229
27.     ItemIndex = 0
28.     Items.Strings = (
29.       'TSquare'
30.       'TCircle'
31.     )
32.     OnClick = rgShapeClick
33.     TabOrder = 0
34.   end
35. end
36.  

[howardpc]

The attached project is how it was meant to be.

[timw4mail]

The attached project is how it was meant to be.

Thanks. After examining the example, I was able to get it working with the following changes: https://git.timshomepage.net/tutorials/lazarus-tutorials/commit/a8c63d1f5afca18bfa5e1149b6bb6c1ce15c5245

Of these changes, what was likely the cause of my problem? Too many referenced units, or the location of the TRadioGroup reference?

[howardpc]

Too many (redundant) units referenced is not a problem. Just unnecessary words in your sources.
The compiler knows what units are required, and ignores any you have included that are not required (and gives you hint(s) that they are not needed).