C＃ReadLine问题

Question

what i want to do is that when people using my program hit enter without anything in there it does not cause an error here is part of the program:

Console.WriteLine("4.-Ya no quiero jugar >.<");
int opc = Convert.ToInt16(Console.ReadLine());

switch (opc)
{
    case 1:
        Console.WriteLine("omg");
        break;

    case 2:
        Console.WriteLine("wtf");
        break;

    default:
        Console.WriteLine("Cant do that  >.>");
        Console.ReadKey();
        break;

    etc.
}

the thing is im using integers,i tried to do this

string opc1=console.readline();

if (opc =="")
{
    console.writeline("nope,try again");
}
else
{ // Brace was omitted in original - Jon
    int opc = Convert.ToInt16(Console.ReadLine());

    switch (opc)

    blah blah.

and different combinations of it >.< and default does not work for that

i hope some one can help me solve it >.<

Answer 1

Check the Int16.TryParse method.

This will allow you to exit from the program or perform another action if the user input is not a number in the range allowed by Int16 (negative 32768 through positive 32767).

Sample code can be found on MSDN entry ( Int16.TryParse Method ).

Answer 2

First, Set your Console.ReadLine() to a variable. Then check to see if the variable you set is not empty or null. Also, I'd recommend using the TryParse method of the Int16 class because it returns true or false depending on if the conversion was successful.

Also, you don't need to convert your ReadLine to an integer, because you can switch on Strings also. Since ReadLine is already a String , no conversion is necessary. However, if you need integers, try this:

String lineIn = Console.ReadLine();

if (!String.IsNullOrEmpty(lineIn))
{
    Int16 myNum;
    if (Int16.TryParse(lineIn , out myNum))
    {
            switch(myNum)
            {
                    case 1:
                    ...
                    default:
                    ...
            }
    }
}

Answer 3

我想你想要的是int.Parse（...）

Answer 4

您可能会考虑使用try catch语句进行错误处理...

Answer 5

TryParse:

string str;
short val;
while(!short.TryParse(str=Console.ReadLine(), out val))
{
    Console.WriteLine("Cant do that  >.>");
}

Answer 6

For getting an integer i usually use a recursive function like this

private int GetInt()
{
     try
     {
         return int.parse(Console.Readline().Trim());
     } 
      catch (exception e) 
     {
         Console.WriteLine(string.format("{0} Please try again", e.message);
         return GetInt();
     }
}