Deletes the item in position nIndex from the list box.
Specifies the zero-based index of the string to be deleted.
A count of the strings remaining in the list. The return value is LB_ERR if nIndex specifies an index greater than the number of items in the list.
All items following nIndex now move down one position. For example, if a list box contains two items, deleting the first item will cause the remaining item to now be in the first position. nIndex=0 for the item in the first position.
// The pointer to my list box.
extern CListBox* pmyListBox;
// Delete every other item from the list box.
for (int i=0;i < pmyListBox->GetCount();i++)
pmyListBox->DeleteString( i );