protected override void OnNavigatedTo(NavigationEventArgs e)
{
PointerPressed += new PointerEventHandler(T_PointerPressed);
PointerReleased += new PointerEventHandler(T_PointerReleased);
PointerMoved += new PointerEventHandler(T_PointerMoved);
equation = e.Parameter as Equation;
DrawGraph();
}
public void Operation(string operation)
{
if (double.TryParse(Display, out double val))
{
if (val == 0)
{
Display = "0";
}
if (!(lastOperator == "/" && Display == "0"))
{
if (lastAction != "+-")
{
if (operators.Contains(lastAction) && lastAction != "=")
{
Equation = Equation.Remove(Equation.Length - 1) + operation;
}
else if (lastAction != "exc")
{
if (lastAction == "=")
{
Equation = "";
}
Equation += Display;
Math(lastOperator, val);
Display = result.ToString();
Equation += operation;
}
lastAction = operation;
lastOperator = operation;
}
}
else
{
ClearAll();
Equation = "Cant divide by zero!";
lastAction = "exc";
}
}
}
public ViewModel()
{
Number = new RelayCommand(
(parameter) =>
{
if (isSumDisplayed || Equation.Equals("0"))
{
Equation = (string)parameter;
}
else
{
Equation += parameter;
}
isSumDisplayed = false;
RefreshCanExecutes();
},
(obj) =>
{
return(isSumDisplayed || Equation.Length < 16);
});
Point = new RelayCommand(
(obj) =>
{
if (Equation.Equals("0"))
{
Equation = "0.";
}
else
{
Equation += ".";
}
isSumDisplayed = false;
RefreshCanExecutes();
},
(obj) =>
{
return(isSumDisplayed || !Equation.Contains("."));
});
Operator = new RelayCommand(
(parameter) =>
{
if (firstOperation)
{
left = Double.Parse(Equation);
firstOperation = false;
rememberOperator = (string)parameter;
HistoryEquation += left.ToString() + parameter;
}
else
{
right = Double.Parse(Equation);
HistoryEquation += right.ToString() + parameter;
switch (rememberOperator)
{
case "+":
left += right;
break;
case "-":
left -= right;
break;
case "*":
left *= right;
break;
case "/":
left /= right;
break;
}
rememberOperator = (string)parameter;
}
Equation = left.ToString();
isSumDisplayed = true;
RefreshCanExecutes();
},
(parameter) =>
{
return(!isSumDisplayed);
});
Ce = new RelayCommand(
(obj) =>
{
left = 0;
HistoryEquation = "";
Equation = "0";
isSumDisplayed = false;
RefreshCanExecutes();
});
C = new RelayCommand(
(obj) =>
{
right = 0;
Equation = "0";
isSumDisplayed = false;
RefreshCanExecutes();
},
(obj) =>
{
return(!isSumDisplayed);
});
Bcs = new RelayCommand(
(obj) =>
{
Equation = Equation.Substring(0, Equation.Length - 1);
if (Equation.Length == 0)
{
Equation = "0";
}
RefreshCanExecutes();
},
(obj) =>
{
return(!isSumDisplayed && (Equation.Length > 1 || Equation[0] != '0'));
});
}
private void operator operatorButtonClicked(Symbol op)
{
if (ERROR_MESSAGE.Equals(_equationText))
{
changeEquationText("0" + op.ToString());
return;
}
var eq = new Equation(_equationText);
if (eq.HasFinalOperator())
{
changeEquationText(eq.ReplaceFinalOperator(op));
} else
{
changeEquationText(_equationText
+ op.ToString());
}
}
private void openParenthesis()
{
Symbol sym = new OpenParenthesis();
if (ERROR_MESSAGE.Equals(_equationText) ||
"0".Equals(_equationText))
{
changeEquationText(sym.ToString());
return;
}
var eq = new Equation(_equationText);
if (!eq.HasFinalOperator())
{
// Disallow a number followed by an open parenthesis
return;
}
changeEquationText(_equationText + sym.ToString());
}
protected void OnButtonDotClicked(object sender, System.EventArgs e)
{
if (ERROR_MESSAGE.Equals(_equationText))
{
changeEquationText("0.");
return;
}
var eq = new Equation(_equationText);
if (!eq.HasFinalOperator())
{
changeEquationText(_equationText + ".");
}
}
