How to delete all rows from QTableWidget

Question

I am trying to delete all rows from a QTableWidget . Here is what I tried.

for ( int i = 0; i < mTestTable->rowCount(); ++i )
{
    mTestTable->removeRow(i);
}

I had two rows in my table. But this just deleted a single row. A reason could be that I did not create the the table with a fixed table size. The Qt Documentation for rowCount() says,

This property holds the number of rows in the table.

By default, for a table constructed without row and column counts, this property contains a value of 0.

So if that is the case, what is the best way to remove all rows from table?

Answer 1

Just set the row count to 0 with:

mTestTable->setRowCount(0);

it will delete the QTableWidgetItems automatically, by calling removeRows as you can see in QTableWidget internal model code:

void QTableModel::setRowCount(int rows)
{
    int rc = verticalHeaderItems.count();
    if (rows < 0 || rc == rows)
        return;
    if (rc < rows)
        insertRows(qMax(rc, 0), rows - rc);
    else
        removeRows(qMax(rows, 0), rc - rows);
}

Answer 2

I don't know QTableWidget but your code seems to have a logic flaw. You are forgetting that as you go round the loop you are decreasing the value of mTestTable->rowCount(). After you have removed one row, i will be one and mTestTable->rowCount() will also be one, so your loop stops.

I would do it like this

while (mTestTable->rowCount() > 0)
{
    mTestTable->removeRow(0);
}

Answer 3

AFAIK setRowCount(0) removes nothing. Objects are still there, but no more visible.

yourtable->model()->removeRows(0, yourtable->rowCount());