private void UpdateChart()
{
int[] letters = new int[26];
foreach (char c in InputField_LetterFrequency_TextBox.Text)
{
if (!char.IsLetter(c))
{
continue;
}
letters[c - 'a']++;
}
for (int i = 0; i < 13; i++)
{
chart1.updateColumnByName(((char)(i + 'a')).ToString(), letters[i]);
chart2.updateColumnByName(((char)(i + 'a' + 13)).ToString(), letters[i + 13]);
}
ColumnChart.Link(chart1, chart2);
chart1.Draw(UpperChart);
chart2.Draw(LowerChart);
}