关于C#winform中的一个小问题，求大神解答！

把编译原理学了 你就能轻松解决这个问题了

在button里编写方法，可以实现，我试过了

#region 四则运算可带括号
/// <summary>
/// 文本框计算器类
/// </summary>
public class Cla
{
/// <summary>
/// Custom结构体 存储符号和索引
/// </summary>
public struct Custom
{
/// <summary>
/// 构造对象
/// </summary>
/// <param name="parenthesis">符号</param>
/// <param name="index">索引</param>
public Custom(string parenthesis, int index)
{
this.parenthesis = parenthesis;
this.index = index;
}
/// <summary>
/// 全局变量符号
/// </summary>
public string parenthesis;
/// <summary>
/// 全局变量索引
/// </summary>
public int index;
}
private List<Custom> Parenthesis = new List<Custom>();
private List<Custom> ReExp = new List<Custom>();
private int ReLeftParenthesis = 0, ReRightParenthesis = 0;
private string Expression = "";
/// <summary>
/// Cla构造函数
/// </summary>
/// <param name="rex">运算表达式("+","-","*","/","(",")")</param>
public Cla(string rex)
{
this.Expression = rex;
}
/// <summary>
/// 获得运算结果
/// </summary>
/// <returns>返回运算结果</returns>
public string GetResult()
{
return this.Operation(this.Expression);
}
private string Operation(string Exp)
{
int LeftParenthesis = 0, RightParenthesis = 0;
if (ReExp.Count != 0)
{
Parenthesis.Clear();
Parenthesis.AddRange(ReExp);
RightParenthesis = ReRightParenthesis;
LeftParenthesis = ReLeftParenthesis;
ReRightParenthesis = 0;
ReLeftParenthesis = 0;
ReExp.Clear();
}
else
{
for (int i = 0; i < Exp.Length; i++)
{
string s = Exp.Substring(i, 1);
if (s == "(")
{
Parenthesis.Add(new Custom(s, i));
LeftParenthesis++;
}
if (s == ")")
{
Parenthesis.Add(new Custom(s, i));
RightParenthesis++;
}
}
}
if (LeftParenthesis == 0 && RightParenthesis == 0 && !Exp.Contains("+") && !Exp.Contains("-") && !Exp.Contains("*") && !Exp.Contains("/"))
return Exp;
if (LeftParenthesis == 1 && RightParenthesis == 1 && !Exp.Contains("+") && !Exp.Contains("-") && !Exp.Contains("*") && !Exp.Contains("/"))
{
Exp = Exp.Replace("(", "");
Exp = Exp.Replace(")", "");
return Exp;
}
if (Parenthesis.Count != 0)
{
if (Parenthesis[0].parenthesis == ")")
{
return "Error!";
}
}
if (LeftParenthesis != RightParenthesis || Exp.Contains("Error!"))
{
return "Error!";
}
if (LeftParenthesis > 1 && RightParenthesis > 1)
{
for (int i = 0; i < Parenthesis.Count - 1; i++)
{
if (Parenthesis[i].parenthesis == "(" && Parenthesis[i + 1].parenthesis == ")")
{
try
{
string result = jisuan(Exp.Substring(Parenthesis[i].index + 1, Parenthesis[i + 1].index - Parenthesis[i].index - 1));
ReExp.AddRange(Parenthesis);
for (int j = i + 2; j <= Parenthesis.Count - 1; j++)
{
int index = Parenthesis[j].index - Exp.Substring(Parenthesis[i].index + 1, Parenthesis[i + 1].index - Parenthesis[i].index - 1).Length - 2 + result.Length;
ReExp[j] = new Custom(Parenthesis[j].parenthesis, index);
}
ReExp.RemoveAt(i);
ReExp.RemoveAt(i);
ReLeftParenthesis = LeftParenthesis - 1;
ReRightParenthesis = RightParenthesis - 1;
return Operation(Exp.Substring(0, Parenthesis[i].index) + result + Exp.Substring(Parenthesis[i + 1].index + 1, Exp.Length - Parenthesis[i + 1].index - 1));
}
catch
{
return "Error!";
}
}
}
}
if (LeftParenthesis == 1 && RightParenthesis == 1)
{
if (Parenthesis[0].index == 0 && Parenthesis[1].index == Exp.Length - 1)
{
return jisuan(Exp.Substring(1, Exp.Length - 2));
}
if (Parenthesis[0].index == 0 && Parenthesis[1].index < Exp.Length - 1)
{
return jisuan(jisuan(Exp.Substring(1, Parenthesis[1].index - 1)) + Exp.Substring(Parenthesis[1].index + 1, Exp.Length - Parenthesis[1].index - 1));
}
if (Parenthesis[1].index == Exp.Length - 1 && Parenthesis[0].index > 0)
{
return jisuan(Exp.Substring(0, Parenthesis[0].index) + jisuan(Exp.Substring(Parenthesis[0].index + 1, Exp.Length - Parenthesis[0].index - 2)));
}
else { return jisuan(Exp.Substring(0, Parenthesis[0].index) + jisuan(Exp.Substring(Parenthesis[0].index + 1, Parenthesis[1].index - Parenthesis[0].index - 1)) + Exp.Substring(Parenthesis[1].index + 1, Exp.Length - Parenthesis[1].index - 1)); }
}
else
{
return jisuan(Exp);
}
}

private string jisuan(string a) //递归四则运算(具有优先级,整数运算)
{
List<Custom> b = new List<Custom>();
string[] yunsuanfu = { "/", "*", "-", "+" };
if (!a.Contains("+") && !a.Contains("-") && !a.Contains("*") && !a.Contains("/"))
return a;
for (int i = 0; i < a.Length; i++)
{
if (a.Substring(i, 1) == "+" || a.Substring(i, 1) == "-" || a.Substring(i, 1) == "*" || a.Substring(i, 1) == "/")
{
b.Add(new Custom(a.Substring(i, 1), i));
}
}
for (int i = 1; i < b.Count; i++)
{
if (b[i - 1].index == b[i].index - 1 && b[i].parenthesis == "-")
{
b.RemoveAt(i);
}
}
for (int j = 0; j < yunsuanfu.Length; j++)
{
for (int i = 0; i < b.Count; i++)
{
if (b[i].parenthesis == yunsuanfu[j])
{
switch (yunsuanfu[j])
{
case "*":// i是符号的位置(0开始),b.count为符号的总个数(1开始)
{
if (i > 0 && i == b.Count - 1) //3+2*2
{
try
{
double a1 = Convert.ToDouble (a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1)); //2
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1)); //2
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 * a2).ToString()); //3+4
}
catch
{
return "Error!";
}
}
if (i == 0 && i < b.Count - 1) //2*2+3+5
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index)); //2
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1)); //2
return jisuan((a1 * a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
} //4+3+5
catch { return "Error!"; }
}
if (i > 0 && i < b.Count - 1) // 2+4/3*6+4
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1)); //3
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1)); //6
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 * a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
} //2+4/18+4
catch { return "Error!"; }
}
if (i == 0 && i == b.Count - 1) //234*231
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index)); //234
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1)); //231
return (a1 * a2).ToString();
}
catch { return "Error!"; }
}
break;
}
case "/":
{
if (i > 0 && i == b.Count - 1) //3+2/2
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1)); //2
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1)); //2
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 / a2).ToString());
} //3+1
catch { return "Error!"; }
}

if (i == 0 && i < b.Count - 1) //2/2+3+5
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index)); //2
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1)); //2
return jisuan((a1 / a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
}//1+3+5
catch { return "Error!"; }
}
if (i > 0 && i < b.Count - 1) // 2+4-6/3+4
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1)); //6
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1)); //3
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 / a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
} //2+4-2+4
catch { return "Error!"; }
}
if (i == 0 && i == b.Count - 1) //24/3
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index)); //24
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1)); //3
return (a1 / a2).ToString();
}
catch { return "Error!"; }
}
break;
}
case "+":
{
if (i > 0 && i == b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1));
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 + a2).ToString());
}
catch { return "Error!"; }
}
if (i == 0 && i < b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1));
return jisuan((a1 + a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
}
catch { return "Error!"; }
}
if (i > 0 && i < b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1));
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 + a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
}
catch { return "Error!"; }
}
if (i == 0 && i == b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1));
return (a1 + a2).ToString();
}
catch { return "Error!"; }
}
break;
}
case "-":
{
if (i > 0 && i == b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1));
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 - a2).ToString());
}
catch { return "Error!"; }
}
if (i == 0 && i < b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1));
return jisuan((a1 - a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
}
catch { return "Error!"; }
}
if (i > 0 && i < b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(b[i - 1].index + 1, b[i].index - b[i - 1].index - 1));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, b[i + 1].index - b[i].index - 1));
return jisuan(a.Substring(0, b[i - 1].index + 1) + (a1 - a2).ToString() + a.Substring(b[i + 1].index, a.Length - b[i + 1].index));
}
catch { return "Error!"; }
}
if (i == 0 && i == b.Count - 1)
{
try
{
double a1 = Convert.ToDouble(a.Substring(0, b[i].index));
double a2 = Convert.ToDouble(a.Substring(b[i].index + 1, a.Length - b[i].index - 1));
return (a1 - a2).ToString();
}
catch { return "Error!"; }
}
break;
}
}
}
}
}
return a;
}
}
#endregion

以前写的 可能有些乱

还有一个简单的办法，但是不知道能支持多少运算符，楼主可以试试
DataTable data = new DataTable();
string result = data.Compute(textBox.Text, "").ToString();
MessageBox.Show(result);
以上方法我试过支持四则运算，其它没试过。