I needed to have the ability to copy/paste from a QTableWidget to a text file. So what I did was created a CustomTableWidget which inherits from QTableWidget. After I created my custom class in Qt creator, I promoted the custom class to the QTableWidgets I created in QtCreator. When I try to compile I get errors in the source that calls the custom class ui_MyForm.h. This file is generated by Qt.

I keep getting emConfigTableWidget is undeclared in this .h file.

I use my custom class like this:
In .h file of my main source file.
CustomTableWidget *emConfigTableWidget;

In the CPP file I use it as such:
#include "ui_MyForm.h"
#include "CustomTableWidget.h"

MyForm(QWidget *parent) :
QWidget(parent),
emConfigTableWidget(new CustomTableWidget)

emConfigTableWidget->horizontalHeader()->setSectionResizeMode(EM_CONFIG_ID_INDEX, QHeaderView::ResizeToContents);

But I get errors in ui_MyForm.h
emConfigTableWidget:undeclared identifier

Would anyone know why this is happening?

My Custom class looks like this:
CustomTableWidget.h
#ifndef CUSTOMTABLEWIDGET_H
#define CUSTOMTABLEWIDGET_H

HIDE_QT_WARNINGS_START

#include <QTableWidget>
#include <QObject>

    class CustomTableWidget : public QTableWidget
    {
         Q_OBJECT

    public:
        CustomTableWidget(QWidget *parent = 0);
        ~CustomTableWidget();
        void copy();
        void paste();

    private:
        QTableWidgetSelectionRange selectedRange();

    };

#endif // CUSTOMTABLEWIDGET_H

CustomTableWidget.cpp looks like this:
#include "CustomTableWidget.h"
#include <QString>
#include <QDebug>
#include <QApplication>
#include <QClipboard>
#include <QTableWidgetSelectionRange>

CustomTableWidget(QWidget *parent) :
QTableWidget(parent)
{

}

~CustomTableWidget()
{

}

void
CustomTableWidget::copy()
{
QTableWidgetSelectionRange range = selectedRange();
QString str;
for (int i = 0; i < range.rowCount(); ++i) {
if (i > 0)
str += "\n";
for (int j = 0; j < range.columnCount(); ++j) {
if (j > 0)
str += "\t";
str += itemAt( range.topRow() + i, range.leftColumn() + j)->text();
}
}
str += "\n";
QApplication::clipboard()->setText(str);

}

QTableWidgetSelectionRange
CustomTableWidget::selectedRange()
{
QList<QTableWidgetSelectionRange> ranges = selectedRanges();
if(ranges.isEmpty())
{
return QTableWidgetSelectionRange();
}

return ranges.first();
}

void
CustomTableWidget::paste()
{
QString str = QApplication::clipboard()->text();
qDebug() << str;
QStringList rows = str.split('\n');
int numRows = rows.count()-1;
int numColumns = rows.first().count('\t') + 1;

qDebug() << numRows << " " << numColumns ;
for (int i = 0; i < numRows; ++i)
{
    QStringList columns = rows[i].split('\t');
    for (int j = 0; j < numColumns; ++j)
    {
          QApplication::clipboard()->setText(rows[i] + columns[j], QClipboard::Clipboard);
    }
}

}