Adding a string to a combobox via the edit control

[HyperEngineer]

I have a problem getting the string out of the edit control of a drop down combo box. I can into the edit control but can't seem to do anything else with it. Here is some code:

{
// TODO: Add your control notification handler code here

// Check that a string is entered
// Get the current selection index
CString strSelected;
CString strAdd;
int nIndex = m_cboString.GetCurSel();
if (nIndex == CB_ERR)
{

m_cboString.GetLBText(-1,strAdd);
m_cboString.AddString(strAdd);
m_cboString.SelectString(0,strAdd);
nIndex = m_cboString.GetCurSel();
}
if (nIndex != CB_ERR)
{
// Store the selection
m_cboString.GetLBText(nIndex, strSelected);

if ((strSelected != "&quot)
{
AfxMessageBox("valid string"
}
else
{
AfxMessageBox("invalid string"
}
}
}
This does not work. GetLBText does not like a negative index. Would appreciate some help.
thanks,
HyperEngineer

 

[palbano]

Yeah i don't know who told you to put a -1 in there. Here is an excerpt from the documentation for that function.

Contains the zero-based index of the list-box string to be copied.

You need to read the document for the functions you are using. Otherwise how do you know what to put in the parameters?

-pete

 

[HyperEngineer]

Pete,
I did read the docs. MSDN can be a bit convoluted at times. I realize it does not say to use -1, but other functions connected with this did use -1, and no definitions of why. Found it in books. However, it also does not tell you how to get the string from the edit box into the list box. I can type into it but can't find anything in the documentation that tells me how to add it to the list. The code was just to show what I had tried. But my problem still remains. How to get the edit control string into the list control of the combo box.

thanks,
Hyper

 

[palbano]

So you need to perform two separate operations yes? Put a new string in a combobox and get the data in the edit box of the combobox.

Now you probably know CComboBox.AddString() puts data into a combobox but there is said it anyway.

To getthe data from the edit control of a combobox variable named "myComboBox", you might do something like this:

 CString sText;
:::GetWindowText( myComboBox.m_hWnd, sText.GetBuffer( 256), 255);
sText.ReleaseBuffer();
// now the text is in sText;

Simple yes? Now comes the “Ohhh” part. How do you know if the user typed a new string in that needs to be added to the combobox or if they just selected an entry that is already in there?

hope that helps
-pete

 

[HyperEngineer]

Thanks Pete,
Looking at your example and going through MSDN to better understand it jogged my memory. I found an easier way. For the code segment when nIndex == CB_ERR I use the UpdateData() function and I have a public variable m_MyCombo.

{
UpdateData(TRUE);
m_cboMyCombo.AddString(m_strMyCombo);
m_cboMyCombo.SelectString(0, m_strMyCombo);
}

Now I can add validation code to make sure that the string is valid and not a duplicate.

Thanks again,
HyperEngineer