private void BtnUndo_Click(object sender, RoutedEventArgs e)
{
if (EquationText.Length - 1 > 0)
{
string s = EquationText.Substring(0, EquationText.Length - 1);
EquationText = s;
}
else
{
EquationText = "";
}
}
public void InsertText(string s)
{
var index = TbEditor.CaretIndex;
if (index == 0)
{
EquationText += s;
}
else
{
EquationText = EquationText.Insert(index, s);
}
}
