再放壹個Button,設置Text為：求解,其單擊後臺代碼如下：
private void button1_Click(object sender, EventArgs e)
{
double a = 0;
double b = 0;
double c = 0;
try
{
if (tbA.Text.Length == 0)
{
MessageBox.Show("請輸入a的值", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
a = Convert.ToDouble(tbA.Text);
}
catch
{
MessageBox.Show("您輸入的a的值不是壹個數字，請重新輸入", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
tbA.Focus();
return;
}
try
{
if (tbB.Text.Length == 0)
{
MessageBox.Show("請輸入b的值", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
b = Convert.ToDouble(tbB.Text);
}
catch
{
MessageBox.Show("您輸入的b的值不是壹個數字，請重新輸入", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
tbB.Focus();
return;
}
try
{
if (tbC.Text.Length == 0)
{
MessageBox.Show("請輸入c的值", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
c = Convert.ToDouble(tbC.Text);
}
catch
{
MessageBox.Show("您輸入的c的值不是壹個數字，請重新輸入", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
tbC.Focus();
return;
}
if (a == 0)
{
if (b == 0)
{
if (c == 0)
{
MessageBox.Show(string.Format("方程{0}x^2+{1}x+{2}=0的解為 x={3}", a, b, c, "任意實數"), "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
else
{
MessageBox.Show(string.Format("方程{0}x^2+{1}x+{2}=0無實數解", a, b, c), "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
else
{
MessageBox.Show(string.Format("方程{0}x^2+{1}x+{2}=0的解為 x={3}", a, b, c, -c / b), "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
else
{
double delta = b * b - 4 * a * c;
if (delta < 0)
{
MessageBox.Show(string.Format("方程{0}x^2+{1}x+{2}=0無實數解", a, b, c), "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
else
{
MessageBox.Show(string.Format("方程{0}x^2+{1}x+{2}=0的解為 x1={3} , x2={4}", a, b, c, (-b + System.Math.Sqrt(delta)) / 2 / a, (-b - System.Math.Sqrt(delta)) / 2 / a), "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}