protected virtual void InitializeTransformSignCommand()
{
TransformSignCommand = new RelayCommand <Button>(
sender => { return(true); }, sender =>
{
char first = Element1[0];
if (first == '0' && Element1.Length == 1)
{
return;
}
if (first == '-')
{
Element1 = Element1.Substring(1);
}
else
{
Element1 = '-' + Element1;
}
});
}