private void buttonModify_Click(object sender, EventArgs e)
        {
            if (listBoxConstraints.SelectedIndex != -1)
            {
                int selectedIndex = listBoxConstraints.SelectedIndex;


                CSPInstanceEntry currentEntry = constraintInstance.createdEntries[selectedIndex];

                currentEntry.constraintName = controller.getConstraints()[comboBoxConstraints.SelectedIndex].Name;
                currentEntry.typedInExpressions.Clear();
                foreach (Expression typedExpression in CSPConstraintDataGridView1.getTypedExpressions())
                {
                    currentEntry.typedInExpressions.Add(typedExpression);
                }

                if (constraintInstance.createdEntries.Count <= selectedIndex)
                {
                    constraintInstance.createdEntries.Insert(selectedIndex, currentEntry);
                }

                constraintInstance.createdEntries[selectedIndex] = currentEntry;

                listBoxConstraints.Items.RemoveAt(selectedIndex);
                listBoxConstraints.Items.Insert(selectedIndex, computeConstraintString(currentEntry));
                listBoxConstraints.SelectedIndex = selectedIndex;
            }
        }
        private void buttonAdd_Click(object sender, EventArgs e)
        {
            if (!this.CSPConstraintDataGridView1.getTypedInValues().Contains(""))
            {
                CSPInstanceEntry currentEntry = new CSPInstanceEntry(repository);
                foreach (Expression expr in CSPConstraintDataGridView1.getTypedExpressions())
                {
                    currentEntry.typedInExpressions.Add(expr);
                }

                currentEntry.constraintName = controller.getConstraints()[comboBoxConstraints.SelectedIndex].Name;
                constraintInstance.createdEntries.Add(currentEntry);

                this.listBoxConstraints.Items.Add(computeConstraintString(currentEntry));
                listBoxConstraints.SelectedIndex = listBoxConstraints.Items.Count - 1;
            }
        }