C# 检查用户输入是否为数字
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原文地址: http://stackoverflow.com/questions/14304591/
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Check if user input is a number
提问by TBK
I want to check if user's input is a number. If yes I want the function to keep running else want to alert him and run it again.
我想检查用户的输入是否是数字。如果是，我希望该功能继续运行，否则想提醒他并再次运行它。
Console.WriteLine(String.Concat("choose your action" ,Environment.NewLine ,
"1.Deposit", Environment.NewLine,
"2.Withdraw", Environment.NewLine,
"3.CheckAccount"));
string c = Console.ReadLine();
int value = Convert.ToInt32(c);
if (value==char.IsLetterOrDigit(value)) //<----- no good why?
{
switch (value)
{
case 1:
Deposit();
return;
case 2:
Withdraw();
return;
case 3:
CheckAccount();
return;
}
}
采纳答案by Mir
Just use:
只需使用：
string c = Console.ReadLine();
int value;
if (int.TryParse(c, out value)) { /*Operate*/ }
EDIT: to adapt the code to the author's comment:
编辑：使代码适应作者的评论：
if (int.TryParse(c, out value) && value >= 1 && value <= 3) { /*Operate*/ }
回答by alpha
int value = Convert.ToInt32(c); this is going to fail if c is not a string consisting of integers only. use try catch to handle this situation.
int 值 = Convert.ToInt32(c); 如果 c 不是仅由整数组成的字符串，这将失败。使用 try catch 来处理这种情况。
