C# 名称在Visual Studio中不存在
因此,我正在为我所在的班级编写一个简单的饮料代码,目前我正在做一些try-catch的东西。当用户单击“清除订单”按钮时,订单将被清除。如果订单已为空,则会抛出错误。不幸的是,如果itemTotal!=0引发错误。当前上下文中不存在名称itemTotal,我不知道这是什么意思。有人能给我点化一下吗C# 名称在Visual Studio中不存在,c#,winforms,visual-studio,C#,Winforms,Visual Studio,因此,我正在为我所在的班级编写一个简单的饮料代码,目前我正在做一些try-catch的东西。当用户单击“清除订单”按钮时,订单将被清除。如果订单已为空,则会抛出错误。不幸的是,如果itemTotal!=0引发错误。当前上下文中不存在名称itemTotal,我不知道这是什么意思。有人能给我点化一下吗 private void checkOutButton_Click(object sender, EventArgs e) { double drinkPri
private void checkOutButton_Click(object sender, EventArgs e)
{
double drinkPrice = 0.0;
double itemTotal = 0.0;
double smDrink = 3.00;
double mdDrink = 3.50;
double lgDrink = 4.00;
int intQuantity;
string strMessage;
if (smallRB.Checked)
{
drinkPrice = smDrink;
}
else if (mediumRB.Checked)
{
drinkPrice = mdDrink;
}
else if (largeRB.Checked)
{
drinkPrice = lgDrink;
}
else
{
MessageBox.Show("Please make a size selection", "Selection Required",
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
double additive = 2.50;
if (vpCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (ebCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (cdCB.Checked)
{
drinkPrice = drinkPrice + additive;
}
}
}
//Calculate extended price and add to order total
if (quantityTextBox.Text != "") //Not blank
{
try
{
intQuantity = int.Parse(quantityTextBox.Text);
itemTotal = drinkPrice * intQuantity;
totalDueTextBox.Text = itemTotal.ToString("C");
}
catch (FormatException err)
{
strMessage = "Nonnumeric data entered for quantity.";
MessageBox.Show(strMessage, "Data Entry Error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}
catch
{
strMessage = "Calculation error.";
MessageBox.Show(strMessage, "Error",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
else //Missing data
{
strMessage = "Enter the quantity.";
MessageBox.Show(strMessage, "Data entry error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}//end if
}
private void clearOrderButton_Click(object sender, EventArgs e)
{
//Clear appropriate controls
if (itemTotal != 0) //User should not be able to clear if not yet calculated
{
veggieRB.Checked = true; //All others are false automatically
smallRB.Checked = false;
mediumRB.Checked = false;
largeRB.Checked = false;
vpCB.Checked = false;
ebCB.Checked = false;
cdCB.Checked = false;
totalDueTextBox.Text = "";
quantityTextBox.Focus();
}
else
{
MessageBox.Show("No New Order to Clear", "Customer Order", MessageBoxButtons.OK);
}
}
现在,您可以在单击事件中使用itemTotal,而无需在单击事件中声明它。如果在事件内声明变量,则变量的范围仅限于该方法 您需要在checkExputton\u Click方法之外声明变量itemTotal,如
double itemTotal = 0.0;
private void checkOutButton_Click(object sender, EventArgs e)
{
double drinkPrice = 0.0;
double smDrink = 3.00;
double mdDrink = 3.50;
double lgDrink = 4.00;
int intQuantity;
string strMessage;
if (smallRB.Checked)
{
drinkPrice = smDrink;
}
else if (mediumRB.Checked)
{
drinkPrice = mdDrink;
}
else if (largeRB.Checked)
{
drinkPrice = lgDrink;
}
else
{
MessageBox.Show("Please make a size selection", "Selection Required",
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
double additive = 2.50;
if (vpCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (ebCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (cdCB.Checked)
{
drinkPrice = drinkPrice + additive;
}
}
}
//Calculate extended price and add to order total
if (quantityTextBox.Text != "") //Not blank
{
try
{
intQuantity = int.Parse(quantityTextBox.Text);
itemTotal = drinkPrice * intQuantity;
totalDueTextBox.Text = itemTotal.ToString("C");
}
catch (FormatException err)
{
strMessage = "Nonnumeric data entered for quantity.";
MessageBox.Show(strMessage, "Data Entry Error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}
catch
{
strMessage = "Calculation error.";
MessageBox.Show(strMessage, "Error",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
else //Missing data
{
strMessage = "Enter the quantity.";
MessageBox.Show(strMessage, "Data entry error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}//end if
}
啊,见鬼,起初我有,但没有我的私人双人房,把它拿走,放弃了,来到这里。啊,我犯了愚蠢的错误,我感谢你的帮助。在这种情况下,你可能会觉得有用。在这种情况下,你可能会觉得有用。
double itemTotal = 0.0;
private void checkOutButton_Click(object sender, EventArgs e)
{
double drinkPrice = 0.0;
double smDrink = 3.00;
double mdDrink = 3.50;
double lgDrink = 4.00;
int intQuantity;
string strMessage;
if (smallRB.Checked)
{
drinkPrice = smDrink;
}
else if (mediumRB.Checked)
{
drinkPrice = mdDrink;
}
else if (largeRB.Checked)
{
drinkPrice = lgDrink;
}
else
{
MessageBox.Show("Please make a size selection", "Selection Required",
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
double additive = 2.50;
if (vpCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (ebCB.Checked)
{
drinkPrice = drinkPrice + additive;
if (cdCB.Checked)
{
drinkPrice = drinkPrice + additive;
}
}
}
//Calculate extended price and add to order total
if (quantityTextBox.Text != "") //Not blank
{
try
{
intQuantity = int.Parse(quantityTextBox.Text);
itemTotal = drinkPrice * intQuantity;
totalDueTextBox.Text = itemTotal.ToString("C");
}
catch (FormatException err)
{
strMessage = "Nonnumeric data entered for quantity.";
MessageBox.Show(strMessage, "Data Entry Error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}
catch
{
strMessage = "Calculation error.";
MessageBox.Show(strMessage, "Error",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
else //Missing data
{
strMessage = "Enter the quantity.";
MessageBox.Show(strMessage, "Data entry error",
MessageBoxButtons.OK, MessageBoxIcon.Information);
quantityTextBox.Focus();
}//end if
}