public void OperationButtonPress(string operation)
{
newDisplayRequired = true;
try
{
if (FirstOperand == String.Empty || LastOperation == "=")
{
FirstOperand = Display;
LastOperation = operation;
Expression = calculation.ToHalfExpressionString(operation);
}
else
{
SecondOperand = Display;
Operation = LastOperation;
calculation.CalculateResult();
Expression = calculation.ToFullExpressionString();
History.Add(String.Format("{0} {1}", Expression, Result));
LastOperation = operation;
Display = Result;
FirstOperand = Display;
}
}
catch (Exception)
{
Display = Result == String.Empty ? "Error" : Result;
}
}
public static string ToHalfExpressionString(this CalculationModel model)
{
return(model.ToHalfExpressionString(model.Operation));
}
