无法执行多个操作 [英] Cannot perform Multiple Operations

问题描述

好吧，我已经完成了这段代码，发现

Well, I've been through this code and found out that

using System; 
using System.Windows; 
//[e-mail]  
//[phone]  
 
using System.Windows.Controls; 
using Microsoft.Phone.Controls; 
 
namespace CalculatorWP 
{ 
    public partial class MainPage : PhoneApplicationPage 
    { 
        // Constructor 
        public MainPage() 
        { 
            InitializeComponent(); 
        } 
 
        private void Number_Click(object sender, RoutedEventArgs e) 
        { 
            Button b = (Button)sender; 
            tb.Text += b.Content.ToString(); 
        } 
 
        private void Result_click(object sender, RoutedEventArgs e) 
        { 
            try 
            { 
                result(); 
            } 
            catch (Exception exc) 
            { 
                tb.Text = "Error!"; 
            } 
        } 
 
        private void result() 
        { 
            String op; 
            int iOp = 0; 
            if (tb.Text.Contains("+")) 
            { 
                iOp = tb.Text.IndexOf("+"); 
            } 
            else if (tb.Text.Contains("-")) 
            { 
                iOp = tb.Text.IndexOf("-"); 
            } 
            else if (tb.Text.Contains("*")) 
            { 
                iOp = tb.Text.IndexOf("*"); 
            } 
            else if (tb.Text.Contains("/")) 
            { 
                iOp = tb.Text.IndexOf("/"); 
            } 
            else 
            { 
                //error 
            } 
 
            op = tb.Text.Substring(iOp, 1); 
            double op1 = Convert.ToDouble(tb.Text.Substring(0, iOp)); 
            double op2 = Convert.ToDouble(tb.Text.Substring(iOp + 1, tb.Text.Length - iOp - 1)); 
 
            if (op == "+") 
            { 
                tb.Text += "=" + (op1 + op2); 
            } 
            else if (op == "-") 
            { 
                tb.Text += "=" + (op1 - op2); 
            } 
            else if (op == "*") 
            { 
                tb.Text += "=" + (op1 * op2); 
            } 
            else 
            { 
                tb.Text += "=" + (op1 / op2); 
            } 
        } 
 
        private void Del_Click(object sender, RoutedEventArgs e) 
        { 
            tb.Text = ""; 
        } 
 
        private void R_Click(object sender, RoutedEventArgs e) 
        { 
            if (tb.Text.Length > 0) 
            { 
                tb.Text = tb.Text.Substring(0, tb.Text.Length - 1); 
            } 
        } 
    } 
}

一切都很好，但主要问题是我不能像3 + 3 + 3那样执行操作，它显示错误信息。请解释我如何做到这一点

Everything is good but the major issue is that I cannot Perform Operations Like 3+3+3, it shows an error message. Please explain me how to do this

推荐答案

上面的代码只会解析表单的公式：A < operator> B。

Your code above will only parse formulas of the form: A <operator> B.

如果你想要一个通用的解析器，
here 是一个使用关键词的搜索：算术解析器c＃

If you want a generic parser, here is a search using the key words: arithmetic parser c#

希望这会有所帮助，

Mark

Hope this helps,
Mark

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