.SetLength in MFC Visual Studio 2008

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I have CString variables declared as public in my class, yet when I try to set a maximum length "m_string1.SetLength(9)" I get a compile error "cannot access private member declared in class 'ATL::CSimpleStringT<BaseType,t_bMFCDLL>::SetLength'.

This is being used in an edit control box.

Beginner here with no concept of what's going on with ATL???

Any help appreciated...

Thanks,

Scott

I want to limit the user to 8 characters of input to an edit control box...
I thought there would be a MAXLENTH in the options where I created the edit boxes, but nothing there.
Guess I need to change from CString to char[9]?

How do I find CString's ("its base class") or any other base class? I have no idea, these are the simple things I'm missing.

Posted 1-Jun-11 5:06am

sbwilliams59

Updated 1-Jun-11 5:57am

v4

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Alain Rist 1-Jun-11 12:05pm

The edit control text length has nothing to do with CString. See my edited answer.

2 solutions

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Alain Rist · Answer 1 · 2011-06-01T05:44:00

Solution 2

Hi Scott,
There is no concept of a maximum length for CString, the length depends on the content.
If you wish to set the allocated size to avoid copying use void CString::Preallocate(int length).
cheers,
AR

Edit after question update:

If you want to limit the length of accepted text for an Edit Control send it the EM_SETLIMITTEXT message:

::SendMessage(hWndofMyControl, EM_SETLIMITTEXT, 8, 0); // limit to 8 characters accepted

Posted 1-Jun-11 5:44am

Alain Rist

Updated 1-Jun-11 6:04am

v2

Comments

sbwilliams59 1-Jun-11 13:58pm

Thanks Alain...that was exactly what I needed...learned how to get a handle in the process (GetDlgItem(m_string)->mWnd).

Scott

Albert Holguin 1-Jun-11 15:44pm

GetDlgItem(m_string) makes no sense btw...

Albert Holguin 1-Jun-11 15:45pm

When you call GetDlgItem(ID) you pass a resource ID of the control you want to get a handle to.

sbwilliams59 1-Jun-11 13:59pm

make that ->m_hWnd

Albert Holguin · Answer 2 · 2011-06-01T05:39:00

Solution 1

Not sure why you're trying to set the length of a CString yourself directly... ???

CStrings are dynamic, meaning they'll allocate any memory themselves based on what data you want them to hold. What are you really trying to do by setting the length of that string?

[edit]
By the way, SetLength is not a member of CString, its a member of its base class, which is why you get the error. Meaning under regular conditions, you shouldn't need to access that member. Are you trying to Truncate()?
[/edit]

Posted 1-Jun-11 5:39am

Albert Holguin

Updated 1-Jun-11 5:46am

v2

Comments

sbwilliams59 1-Jun-11 14:06pm

Albert,
I could have posed the question better...thanks for the input.
Scott

Albert Holguin 1-Jun-11 15:44pm

I see what you were trying to achieve now, yep, that has nothing to do with CString

sbwilliams59 1-Jun-11 16:11pm

and m_string was what I had tied to the control, not the actual control IDC_yada...again, I misspoke.

Albert Holguin 1-Jun-11 16:26pm

lol, ok... as long as you're learning as you go...