private void CalculateButton_Click(object sender, EventArgs e)
{
if (HeightTextBox == null || HeightTextBox.Text == "")
{
BMIRichTextBox.Clear();
HeightTextBox.AppendText("Text cannot be null");
}
if (WeightTextBox == null || WeightTextBox.Text == "")
{
BMIRichTextBox.Clear();
WeightTextBox.AppendText("Text cannot be null");
}
else
{
BMIRichTextBox.Clear();
Calculate();
}
}