CStringArray has no copy constructor

http://cgdev.iworld.com/forum/showthread.php?t=80126
The error is obvious: CStringArray has no copy constructor, while CString does. If you do not understand what a copy constructor is, I suggest you get a book on C++ and learn about this.

I'll give you a brief description of the symptoms and how to solve this:

The difference between CString and CStringArray is this:

A CString holds a single string. A CStringArray holds an array of strings.

Here is where the copy constructor comes in:

The CString can be assigned to a CString. For example, I can do this:

CString a;
CString b = a; // copy constructor



A CStringArray can not be assigned to another CStringArray. Why? because the creator of class CStringArray decided that copying each string into another array would be wasteful and time consuming (imagine if you had an array of 100,000 strings, and each string had 100,000 characters!)

CStringArray a;
CStringArray b = a; // Cannot be done, no copy constructor defined



Now, if you really want to assign a CStringArray to a CStringArray, you have to create your own copy constructor first. The way to do this is that you must derive a class from CStringArray, and create the copy in the derived class.

class CMyStringArray : public CStringArray
{
public:
CMyStringArray{CMyStringArray& a) {
Copy(a);
};



I called the CStringArray::Copy() function to copy the elements into my class. Another way you can solve your problems is to change your function:

void CMRecordset::GetFieldNames(CStringArray& A)
{
A.Copy(m_strFieldNames);
}



Note that you pass a CStringArray to the function, and the function copies the values to the array.

I hope this helps.

Regards,

Paul McKenzie

posted on 2006-01-16 21:10  cy163  阅读(...)  评论(...编辑  收藏

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