private void BtnOK_Click(object sender, EventArgs e)
{
try
{
int num = Convert.ToInt32(TxtNum.Text);
int sum = 0;
string msg = "1到" + num + "被7整除的數：\n";
if (num > 7 && num < 100)
{
for (int i = 1; i < num; i++)
{
if (i >= 7 && i % 7 == 0)
{
msg += i + "\n";
sum += i;
}
}
msg += "------------\n" + "總和等於" + sum;
MessageBox.Show(msg);
}
else
{
MessageBox.Show("請輸入大於7小於100的正整數", "錯誤");
TxtNum.Focus();
}
}
catch
{
MessageBox.Show("請輸入數字", "錯誤");
TxtNum.Focus();
}
}
//點選購買物品的清單項目時
private void LstName_SelectedIndexChanged(object sender, EventArgs e)
{
if (LstName.SelectedIndex >= 0) //若選項的註標值>= 0
{
TxtName.Text = LstName.Text; //顯示品名
TxtPrice.Text = s_price[LstName.SelectedIndex].ToString(); //顯示單價
TxtNum.Text = "1"; //預設數量為1
TxtTotal.Text = ""; //預設小計為空字串
TxtNum.Focus(); //txtNum設為停駐焦點
}
}
private void LstName_SelectedIndexChanged(object sender, EventArgs e)
{
if (LstName.SelectedIndex >= 0)
{
TxtName.Text = LstName.Text;
TxtPrice.Text = s_price[LstName.SelectedIndex].ToString();
TxtNum.Text = "1";
TxtTotal.Text = "";
TxtSum.Text = "";
TxtNum.Focus();
}
}
private bool ValidateInput()
{
if (TxtCId.Text == "") //验证是否输入了班级代码
{
MessageBox.Show("请输入班级号！", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Information);
TxtCId.Focus();
return(false);
}
if (TxtCName.Text == "") //验证是否输入了班级名称
{
MessageBox.Show("请输入班级名称！", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Information);
TxtCName.Focus();
return(false);
}
if (TxtNum.Text == "") //验证是否输入了人数
{
MessageBox.Show("请输入学生人数！", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Information);
TxtNum.Focus();
return(false);
}
return(true);
}