【发布时间】：2011-11-16 11:27:37
【问题描述】：
它告诉我我创建的名为“计算”的方法“并非所有代码路径都返回值” 如果您想知道，这是家庭作业，我是一年级的编程学生。我只是想摆脱这个错误，如果我将它更改为静态方法，它就会消失，但是我遇到了我所做的验证错误的问题。
private decimal Calculate(decimal operand1, decimal operand2, string operator1)
{
//Declarations
decimal operandOne;
decimal operandTwo;
string operatorOne = "";
const string divide = "/";
const string multiply = "*";
const string addition = "+";
decimal calcResult = 0m;
try
{
if (IsValidData())
{
// try to get the user input from the form
operandOne = Convert.ToDecimal(txtOperandOne.Text);
operandTwo = Convert.ToDecimal(txtOperandTwo.Text);
operatorOne = Convert.ToString(txtOperator.Text);
if (operatorOne == divide)
{
calcResult = operandOne / operandTwo;
}
else if (operatorOne == multiply)
{
calcResult = operandOne * operandTwo;
}
else if (operatorOne == addition)
{
calcResult = operandOne + operandTwo;
}
else
{
calcResult = operandOne - operandTwo;
}
return (Math.Round(calcResult, 4));
}
}
catch (FormatException myFormatEx)
{
MessageBox.Show(myFormatEx.Message + "\nInvalid numeric format. Please check all entries.", "Entry Error");
}
catch (OverflowException myOverflowEx)
{
MessageBox.Show(myOverflowEx.Message + "\nOverflow error. Please enter smaller values.", "Entry Error");
}
catch (Exception myEx)
{
MessageBox.Show(myEx.Message + "\n\n" + myEx.GetType().ToString() + "\n" + myEx.StackTrace, "Exception");
}
}
private void btnCalculate_Click(object sender, EventArgs e)
{
//DECLARATIONS
decimal calcResult;
decimal operandOne = 0m;
decimal operandTwo = 0m;
string operatorOne = "";
//PROCESSING
calcResult = Calculate(operandOne, operandTwo, operatorOne);
//OUTPUT
lblResult.Text = calcResult.ToString("d"); // in decimal format
}
private bool IsValidData()
{
// This method checks all the textboxes on the form for valid entries
return
// Validate the OperandOne text box
IsPresent(txtOperandOne, "First Operator") &&
IsDecimal(txtOperandOne, "First Operator") &&
// Validate the OperandTwo text box
IsPresent(txtOperandTwo, "Second Operator") &&
IsDecimal(txtOperandTwo, "Second Operator") &&
// Validate the Operator text box
IsPresent(txtOperator, "Operator /,*,+ or -") &&
IsOperator(txtOperator, "Operator /,*,+ or -");
}
public bool IsOperator(TextBox textBox, string name)
{
// this method makes sure a textbox is a valid operator
string validOperators = "";
bool valid = true;
try
{
validOperators = Convert.ToString(textBox.Text); // try to convert
if (validOperators != "/" | validOperators != "*" | validOperators != "+" | validOperators != "-") // not valid entry
{
MessageBox.Show(name + " must be a valid operator +,-,/,* Entry Error");
textBox.SelectAll();
valid = false;
}
}
catch (FormatException myFormatEx)
{
textBox.SelectAll(); // Select the user's entry
throw myFormatEx; // throw to the calling method to handle
}
catch (OverflowException myOverflowEx)
{
throw myOverflowEx; // throw to the calling method to handle
}
catch (Exception myEx)
{
throw myEx; // throw to the calling method to handle
}
return valid;
}
public bool IsPresent(TextBox textBox, string name)
{
// this method checks any textbox for a required entry
bool valid = true; // assuming valid
if (textBox.Text == "") // check to see if there is an entry
{
MessageBox.Show(name + " is a required field.", "Entry Error");
textBox.Focus(); // set the focus
valid = false;
}
return valid;
}
public bool IsDecimal(TextBox textBox, string name)
{
// this method checks any textbox for a valid decimal entry
bool valid = true; // assuming valid
try
{
Convert.ToDecimal(textBox.Text);
}
catch (FormatException)
{
MessageBox.Show(name + " must be a decimal value.", "Entry Error");
textBox.SelectAll(); // Select the user's entry
valid = false;
}
catch (OverflowException myOverflowEx)
{
throw myOverflowEx; // throw to the calling method to handle
}
catch (Exception myEx)
{
throw myEx; // throw to the calling method to handle
}
return valid;
}
private void btnExit_Click(object sender, EventArgs e)
{
//End program
this.Close();
}
}
}
【问题讨论】：
标签： c# calculator