〔求助〕小弟刚学winform.想弄个计算机，有代码不清楚，

Double sum = 0;
Boolean blnClear = false;
String strOper="+";
//《求助代码区》
private void btnjiahao_Click(object sender, EventArgs e)
{
//为加号按钮区
double dbSecond = Convert.ToDouble(textBox1.Text);
if (!blnClear)
switch (strOper)
{
case "+": sum += dbSecond; break;
case "-": sum -= dbSecond; break;
case "*": sum = sum * dbSecond; break;
case "/": sum = sum / dbSecond; break;
}
if (sender == btnjiahao)
strOper = "+";
if (sender == btnjianhao)
strOper = "-";
if (sender == btnchenghao)
strOper = "*";
if (sender == btnchuhao)
strOper = "/";
if (sender == btndenghao)
strOper = "=";
textBox1.Text = Convert.ToString(sum);
blnClear = true;
}

拜托了

计算机...............会写内核吗？设计好ui没？解决驱动问题了吗？优化的怎么样？安全性如何？开机快不快。
卤煮只是想做个计算器而已你想这么多干嘛！

if (!blnClear)，哪里没报错么。

public partial class Form1 : Form
{
bool flag = true;
long op1 = 0, op2 = 0;
string sign = "";
public Form1()
{
InitializeComponent();
}
private void button0_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
if (flag == true)
{
textBox1.Text = "";
flag = false;
}
if (textBox1.Text.Equals("0"))
{
textBox1.Text = btn.Text;
}
else
{
textBox1.Text = textBox1.Text + btn.Text;
}
}
private void button_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
if (sign == "")
{
sign = btn.Text;
flag = true;
op1 = long.Parse(textBox1.Text);
}
else
{
op2 = long.Parse(textBox1.Text);
switch (sign)
{
case "+": op2 = op2 + op1;
break;
case "-": op2 = op1 - op2;
break;
case "*": op2 = op1 * op2;
break;
case "/": op2 = op1 / op2;
break;
}
textBox1.Text = op2.ToString();
op1 = long.Parse(textBox1.Text);
flag = true;
sign = btn.Text;
}
}

private void button_deng_Click(object sender, EventArgs e)
{
if (sign.Equals(""))
{
return;
}
op2 = long.Parse(textBox1.Text);
switch (sign)
{
case "+": op2 = op2 + op1;
break;
case "-": op2 = op1 - op2;
break;
case "*": op2 = op1 * op2;
break;
case "/": op2 = op1 / op2;
break;
}
textBox1.Text = op2.ToString();
op1 = op2 = 0;
flag = true;
sign = "";
}
private void button_neg_Click(object sender, EventArgs e)
{
if (!textBox1.Text.Equals("0"))
{
if (textBox1.Text.Substring(0, 1).Equals("-"))//如果前面已经有-号了
{
textBox1.Text = textBox1.Text.Substring(1);//去掉前面的-号
}
else
{
textBox1.Text = "-" + textBox1.Text;//没-号则加上-号
}
}
}
private void button_backspace_Click(object sender, EventArgs e)
{
if (textBox1.Text.Length == 1)
{
textBox1.Text = "0";
}
else
{
textBox1.Text = textBox1.Text.Substring(0, textBox1.Text.Length - 1);
if (textBox1.Text.Equals("-"))
{
textBox1.Text = "0";
}
}
}
private void button_clear_Click(object sender, EventArgs e)
{
textBox1.Text = "0";
op1 = op2 = 0;
flag = false;
sign = "";
}
}