如果用户必须输入整数，如何在我的 if 语句中设置条件？ C＃

Question

//Hold the Roses' cost
decimal numberofRoses;//user's desired number of roses
decimal totalCostofRoses; //the total amount of the roses' price
const decimal COST_PER_ROSE = 10;//each rose cost 10 dollars

//Get the user's input
numberofRoses = decimal.Parse(rosesTextBox.Text);

if ()//Require a condition where the user has to type in a whole number
{

}
else
{
    MessageBox.Show("Please input a whole number for the number of roses");
}

Answer 1

除以1余数为0为整数:

if ((numberofRoses % 1) == 0) 
{

}

您还可以使用 Int32.TryParse() 将数字解析为 int，这样会更有效：

int roses = 0;
if (int.TryParse(numberofRoses, out roses)
{
    //"roses" is now an int (Whole number)
}

Answer 2

您可以使用 TryParse() :

int num; // use a int not a decimal. You dont want half of a rose.
if (Int32.TryParse(rosesTextBox.Text, out num)
{
    // do something with num. it is an int.
}
else
{
    MessageBox.Show("Please input a whole number for the number of roses");
}