Question

我在世界上如何设置try和catch来阻止用户输入多个小数。这是尝试和捕捉？或者我到底想做什么？ Windows窗体应用程序的新功能......

还有一些需要注意的事项......当我点击计算时，数字会消失......它不会一直停留在那里。我觉得这很奇怪。谁会知道为什么？例如，如果我达到6 + 6则显示＆＃34; 6＆＃34;然后另一个＆＃34; 6＆＃34;然后是12，而不是显示6 + 6 = 12。我也不明白

编辑：这是一个更新的代码。我有一切，除了我还不知道如何不断编写代码。当我被困住时，欢迎任何建议......

public partial class Form1 : Form
{
    char c;
    double num1;
    double num2;

    public Form1()
    {
        InitializeComponent();
    }
    private void btn0_Click(object sender, EventArgs e)
    {
        txtBox.Text += 0;
    }
    private void btn1_Click(object sender, EventArgs e)
    {
        txtBox.Text += 1;
    }
    private void btn2_Click(object sender, EventArgs e)
    {
        txtBox.Text += 2;
    }
    private void btn3_Click(object sender, EventArgs e)
    {
        txtBox.Text += 3;
    }
    private void btn4_Click(object sender, EventArgs e)
    {
        txtBox.Text += 4;
    }
    private void btn5_Click(object sender, EventArgs e)
    {
        txtBox.Text += 5;
    }
    private void btn6_Click(object sender, EventArgs e)
    {
        txtBox.Text += 6;
    }
    private void btn7_Click(object sender, EventArgs e)
    {
        txtBox.Text += 7;
    }
    private void btn8_Click(object sender, EventArgs e)
    {
        txtBox.Text += 8;
    }
    private void btn9_Click(object sender, EventArgs e)
    {
        txtBox.Text += 9;
    }
    private void btnDecimal_Click(object sender, EventArgs e)
    {
        if (!txtBox.Text.Contains("."))
            txtBox.Text += ".";
    }
    private void btnAddition_Click(object sender, EventArgs e)
    {
        c = '+';
        num1 = double.Parse(txtBox.Text);
        txtBox.Text = string.Empty;
    }
    private void btnSubtraction_Click(object sender, EventArgs e)
    {
        c = '-';
        num1 = double.Parse(txtBox.Text);
        txtBox.Text = string.Empty;
    }
    private void btnMultiplication_Click(object sender, EventArgs e)
    {
        c = '*';
        num1 = double.Parse(txtBox.Text);
        txtBox.Text = string.Empty;
    }
    private void btnDivision_Click(object sender, EventArgs e)
    {
        c = '/';
        num1 = double.Parse(txtBox.Text);
        txtBox.Text = string.Empty;
    }
    private void btnClear_Click(object sender, EventArgs e)
    {
        txtBox.Clear();
    }
    private void btnEqual_Click(object sender, EventArgs e)
    {
        num2 = double.Parse(txtBox.Text);
        double result;
        switch (c)
        {
            case '+':
                result = num1 + num2;
                txtBox.Text = result.ToString();
                break;
            case '-':
                result = num1 - num2;
                txtBox.Text = result.ToString();
                break;
            case '/':
                 if (num2!= 0) 
                {
                    result = num1 / num2;
                    txtBox.Text = result.ToString();
                } 
                else 
                {
                    txtBox.Text = "You can't divide by zero... sign up for Math 100 please =)";
                } 
                break; 
            case '*':
                result = num1 * num2;
                txtBox.Text = result.ToString();
                break;
        }
    }
}

}

Answer 1

首先，您不需要try catch语句。 try catch语句用于异常处理。

清除之后，您想要的是将当前输入添加到您保留在内存中并在屏幕上显示的数字的单一方法。我不会向你展示代码，因为你有很多东西要改变，但基本上你应该看一下calculator example

Answer 2

是的你不需要试试catch阻止它进行异常处理，你必须改变你的代码，所以可能你试试这个可以帮助你............

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 

namespace SimpleCalculator 
{ 
    public partial class frmCalculator : Form 
    { 
        string operand1 = string.Empty; 
        string operand2 = string.Empty; 
        string result; 
        char operation; 

        public frmCalculator() 
        { 
            InitializeComponent(); 
        } 

        private void frmCalculator_Load(object sender, EventArgs e) 
        { 
            btnOne.Click += new EventHandler(btn_Click); 
            btnTwo.Click += new EventHandler(btn_Click); 
            btnThree.Click += new EventHandler(btn_Click); 
            btnFour.Click += new EventHandler(btn_Click); 
            btnFive.Click += new EventHandler(btn_Click); 
            btnSix.Click += new EventHandler(btn_Click); 
            btnSeven.Click += new EventHandler(btn_Click); 
            btnEight.Click += new EventHandler(btn_Click); 
            btnNine.Click += new EventHandler(btn_Click); 
            btnZero.Click += new EventHandler(btn_Click); 
            btnDot.Click += new EventHandler(btn_Click); 
        } 

        void btn_Click(object sender, EventArgs e) 
        { 
            try 
            { 
                Button btn = sender as Button; 

                switch (btn.Name) 
                { 
                    case "btnOne": 
                        txtInput.Text += "1"; 
                        break; 
                    case "btnTwo": 
                        txtInput.Text += "2"; 
                        break; 
                    case "btnThree": 
                        txtInput.Text += "3"; 
                        break; 
                    case "btnFour": 
                        txtInput.Text += "4"; 
                        break; 
                    case "btnFive": 
                        txtInput.Text += "5"; 
                        break; 
                    case "btnSix": 
                        txtInput.Text += "6"; 
                        break; 
                    case "btnSeven": 
                        txtInput.Text += "7"; 
                        break; 
                    case "btnEight": 
                        txtInput.Text += "8"; 
                        break; 
                    case "btnNine": 
                        txtInput.Text += "9"; 
                        break; 
                    case "btnZero": 
                        txtInput.Text += "0"; 
                        break; 
                    case "btnDot": 
                        if(!txtInput.Text.Contains(".")) 
                            txtInput.Text += "."; 
                        break; 

                } 
            } 
            catch(Exception ex) 
            { 
                MessageBox.Show("Sorry for the inconvenience, Unexpected error occured. Details: " + 
                    ex.Message); 
            } 
        } 

        private void txtInput_KeyPress(object sender, KeyPressEventArgs e) 
        { 
            switch (e.KeyChar) 
            { 
                case '1': 
                case '2': 
                case '3': 
                case '4': 
                case '5': 
                case '6': 
                case '7': 
                case '8': 
                case '9': 
                case '0': 
                //case '+': 
                //case '-': 
                //case '*': 
                //case '/': 
                //case '.': 
                    break; 
                default: 
                    e.Handled = true; 
                    MessageBox.Show("Only numbers, +, -, ., *, / are allowed"); 
                    break; 
            }            
        } 

        private void txtInput_TextChanged(object sender, EventArgs e) 
        { 

        } 

        private void btnPlus_Click(object sender, EventArgs e) 
        { 
            operand1 = txtInput.Text; 
            operation = '+'; 
            txtInput.Text = string.Empty; 
        } 

        private void btnMinus_Click(object sender, EventArgs e) 
        { 
            operand1 = txtInput.Text; 
            operation = '-'; 
            txtInput.Text = string.Empty; 
        } 

        private void btnMulitply_Click(object sender, EventArgs e) 
        { 
            operand1 = txtInput.Text; 
            operation = '*'; 
            txtInput.Text = string.Empty; 
        } 

        private void btnDivide_Click(object sender, EventArgs e) 
        { 
            operand1 = txtInput.Text; 
            operation = '/'; 
            txtInput.Text = string.Empty; 
        } 

        private void btnEqual_Click(object sender, EventArgs e) 
        { 
            operand2 = txtInput.Text; 

            double opr1, opr2; 
            double.TryParse(operand1, out opr1); 
            double.TryParse(operand2, out opr2); 

            switch (operation) 
            { 
                case '+': 
                    result = (opr1 + opr2).ToString(); 
                    break; 

                case '-': 
                    result = (opr1 - opr2).ToString(); 
                    break; 

                case '*': 
                    result = (opr1 * opr2).ToString(); 
                    break; 

                case '/': 
                    if (opr2 != 0) 
                    { 
                        result = (opr1 / opr2).ToString(); 
                    } 
                    else 
                    { 
                        MessageBox.Show("Can't divide by zero"); 
                    } 
                    break; 
            } 

            txtInput.Text = result.ToString(); 
        } 

        private void btnClear_Click(object sender, EventArgs e) 
        { 
            txtInput.Text = string.Empty; 
            operand1 = string.Empty; 
            operand2 = string.Empty; 
        } 

        private void btnSqrRoot_Click(object sender, EventArgs e) 
        { 
            double opr1; 
            if (double.TryParse(txtInput.Text, out opr1)) 
            { 
                txtInput.Text = (Math.Sqrt(opr1)).ToString(); 
            } 
        } 

        private void btnByTwo_Click(object sender, EventArgs e) 
        { 
            double opr1; 
            if (double.TryParse(txtInput.Text, out opr1)) 
            { 
                txtInput.Text = (opr1 / 2).ToString(); 
            } 
        } 

        private void btnByFour_Click(object sender, EventArgs e) 
        { 
            double opr1; 
            if (double.TryParse(txtInput.Text, out opr1)) 
            { 
                txtInput.Text = (opr1 / 4).ToString(); 
            } 
        } 
    } 
}

try和catch语句有困难吗？

2 个答案: