我是c＃的新手。我正在尝试用c＃构建计算器。一切正常，小数点系统工作正常，但我的主要问题是我不希望小数重复多次。目前如果我把0.1 + 0.1我会得到0.2。但是我想要像计算器一样使用小数点。我确实将构造函数中的条件设置为isDecimal = false并在此之后创建新数字。所以它会认识到并且失败了。有人可以帮我解决我做错的事吗。谢谢。请尝试给出简单的解释，以便我能理解，而且我也是新的
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Calc
{
public partial class Form1 : Form
{
/// <summary>
/// This is a constructor which will run atleast once. This will also create new number
/// </summary>
public Form1()
{
InitializeComponent();
memory = 0;
txtResult.Text = "0";
t = 0;
h = 0;
count = 0;
//boolean Type
isDecimal = false;
creatingNewNumber = true; // saying we we want to create the new number
}
private double leftSide;
private bool creatingNewNumber;
private double rightSide;
private double memory;
private string operators;
private double t;
private double h;
private double count;
private bool isDecimal;
/// <summary>
/// A function to add two numbers.
/// </summary>
/// <param name="x">Left Side of an addition</param>
/// <param name="y">Right Side of an addition</param>
/// <returns>Returns the answer to the addition.</returns>
public double add(double x, double y)
{
//do sdome work
leftSide = x;
rightSide = y;
double z = leftSide + rightSide;
return z;
}
/// <summary>
/// Function to add substract
/// </summary>
/// <param name="x">Left Side </param>
/// <param name="y">Right Side</param>
/// <returns>Returns the answer in substraction</returns>
public double substract(double x, double y)
{
leftSide = x;
rightSide = y;
double s = leftSide - rightSide;
return s;
}
/// <summary>
/// Function to call the multiply
/// </summary>
/// <param name="x">Left side</param>
/// <param name="y">Right Side</param>
/// <returns>Returns the value in multiplication</returns>
public double multiply(double x, double y)
{
leftSide = x;
rightSide = y;
double m = leftSide * rightSide;
return m;
}
/// <summary>
/// function to call the division and also stating that if the number on right is 0 throw an error.
/// </summary>
/// <param name="x">Left Side</param>
/// <param name="y">Right Side</param>
/// <returns>Return the value in division</returns>
public double divide(double x, double y)
{
double d;
leftSide = x;
rightSide = y;
if (rightSide == 0)
{
MessageBox.Show("Cannot divide by zero");
return 0;
}
else
{
d = leftSide / rightSide;
}
return d;
}
/// <summary>
/// The function does division. In addition what it does is store the memory value in y and
/// then at last it creates the conditional value wheather to create new value or to append
/// the value when the operator is press which is (+-*/)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void divide_Click(object sender, EventArgs e) // divide
{
bool StillOK = true;
double y;
if (!double.TryParse(txtResult.Text, out y))
{
MessageBox.Show("Right Side is not a valid number");
StillOK = false;
}
if (StillOK)
{
memory = y;
operators = "/";
creatingNewNumber = true;
}
}
/// <summary>
/// The function does division. In addition what it does is store the memory value in y and
/// then at last it creates the conditional value wheather to create new value or to append
/// the value when the operator is press which is (+-*/)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void multiply_Click(object sender, EventArgs e) // multiply function
{
bool StillOK = true;
double y;
if (!double.TryParse(txtResult.Text, out y))
{
MessageBox.Show(txtResult.Text + " is not a valid number");
StillOK = false;
}
if (StillOK)
{
memory = y;
operators = "*";
creatingNewNumber = true;
}
}
/// <summary>
/// The function does division. In addition what it does is store the memory value in y and
/// then at last it creates the conditional value wheather to create new value or to append
/// the value when the operator is press which is (+-*/)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void add_Click(object sender, EventArgs e) // add function
{
bool StillOK = true;
double y;
if (!double.TryParse(txtResult.Text, out y))
{
MessageBox.Show(txtResult.Text + " is not a valid number");
StillOK = false;
}
if (StillOK)
{
memory = y;
operators = "+";
creatingNewNumber = true;
}
}
/// <summary>
/// The function does division. In addition what it does is store the memory value in y and
/// then at last it creates the conditional value wheather to create new value or to append
/// the value when the operator is press which is (+-*/)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void substract_Click(object sender, EventArgs e) // substract function
{
bool StillOK = true;
double y;
if (!double.TryParse(txtResult.Text, out y))
{
MessageBox.Show(txtResult.Text + " is not a valid number");
StillOK = false;
}
if (StillOK)
{
memory = y;
operators = "-";
creatingNewNumber = true;
}
}
/// <summary>
/// This function resets the Txt Result box to zero
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button5_Click(object sender, EventArgs e) // clear function
{
memory = 0;
txtResult.Text = "0";
creatingNewNumber = true;
}
/// <summary>
/// This Function will focus on decimal Point
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button19_Click(object sender, EventArgs e) //decimal point ( . )
{
if (isDecimal)
{
txtResult.Text = ".";
isDecimal = true;
creatingNewNumber = true;
}
txtResult.Text += "."; // should add one more decimal point
}
private void button14_Click(object sender, EventArgs e)
{
double equal;
if (!double.TryParse(txtResult.Text, out equal))
{
MessageBox.Show(txtResult + "This is not an valid.");
}
else
{
switch (operators)
{
case "+":
memory = add(memory, equal);
break;
case "-":
memory = substract(memory, equal);
break;
case "/":
memory = divide(memory, equal);
break;
case "*":
memory = multiply(memory, equal);
break;
default:
break;
}
txtResult.Text = memory.ToString(); // convert text to string result
creatingNewNumber = true;
}
}
我做错了什么？任何建议都将受到欢迎。谢谢你的帮助
编辑：现在我可以点击0..1我试图阻止它，只想显示0.1（不再使用。应该允许使用。）
答案 0 :(得分：1)
我不确定为什么你需要在你的十进制块中使用所有这些
private void button19_Click(object sender, EventArgs e)
{
if (isDecimal)
{
txtResult.Text = ".";
isDecimal = true;
creatingNewNumber = true;
}
txtResult.Text += "."; // should add one more decimal point
}
应该是这样的
private void button19_Click(object sender, EventArgs e)
{
if (txtResult.Text == string.Empty || txtResult.Text.IndexOf('.') > -1)
return;
txtResult.Text += ".";
}
注意：我看到这里的其他答案会告诉你一些关于文本验证，关键新闻事件等等 - 你不需要关于文本框。所有表格按键都应指向按钮点击。文本框应该是只读的，一旦你禁用任何直接的键盘到文本框输入，你只需要检查是否按下了按钮＆＃34;。＆＃34;，如果点已经存在绕过。
答案 1 :(得分：0)
进行此类文本验证的一种方法是使用正则表达式：
^[0-9]+(\.[0-9]+)?$
其中
^表示＆＃34;字符串的开头＆＃34;
[0-9]+表示＆＃34; 1个或更多数字＆＃34; （[...]表示字符类 - 即字符的选择）
$表示＆＃34;字符串结尾＆＃34;
\.表示一个文字句点（通常，.表示＆＃34;任何字符都是＆＃34; - 反斜杠表示它是一个替代意义而不是＆＃34;通常＆ ＃34;含义）
?表示＆＃34; 0或1次＆＃34; （即小数部分是可选的，但是如果他们拥有它只能出现一次）
这会导致无效输入的一些示例：
答案 2 :(得分：0)
好的所以我找到了答案，零确实包含了。 更新代码
if (creatingNewNumber == true)
{
if (txtResult.Text.IndexOf('.') == -1)
{
creatingNewNumber = false;
txtResult.Text += ".";
}
else
{
txtResult.Text = "0.";
creatingNewNumber = false;
}
答案 3 :(得分：0)
我不知道您是显示数学运算还是仅显示最终结果，但如果您在文本框中显示完整操作（例如; 5 + 1.2 = 6.2），以下内容可帮助您进行一些验证关于文字的变化：
private void textBox1_TextChanged(object sender, EventArgs e)
{
int lastOperatorIndex = ((TextBox)sender).Text.LastIndexOfAny(new char[] { '+', '-', '/', '*' });
lastOperatorIndex = lastOperatorIndex < 0 ? 0: lastOperatorIndex + 1;
// Check if the new added character is '.' and the if last number has already a decimal point then prevent the change.
if (((TextBox)sender).Text.Last().Equals('.') && ((TextBox)sender).Text.Substring(lastOperatorIndex, textBox1.Text.Length - lastOperatorIndex - 1 ).Contains('.'))
{
textBox1.Text = textBox1.Text.Substring(0, textBox1.Text.Length - 1);
}
}
答案 4 :(得分：-1)
将TextChanged事件添加到您的输入中。在TextChanged事件中，添加
myInput = new Regex("[.]{2,}", RegexOptions.None).Replace(myInput, ".");
这将在用户输入时进行处理，如果他们复制粘贴，并且会在他们尝试处理的任何时候覆盖＆＃34;。＆＃34;。
为了使用户能够很好地处理，可以使用简单的插入符号控件：
private void textBox1_TextChanged(object sender, EventArgs e)
{
int currentCharIndex = textBox1.SelectionStart;
Regex r = new Regex("[.]{2,}", RegexOptions.None);
if (r.IsMatch(textBox1.Text))
{
textBox1.Text = r.Replace(textBox1.Text, ".");
if(textBox1.SelectionStart > 0)
textBox1.SelectionStart = currentCharIndex - 1;
}
}
（警告，对于非常大的字符串输入，这可能效率很低，但对于你正在做的事情，它应该处理得很好）。
编辑：如果您点击按钮，它将删除焦点，固定使其只有在索引大于0时才会执行此操作（如果没有焦点或在开头时它为0）