添加开关外壳

Question

我想添加开关大小写，不允许用户在输入温度时写入字符串，或者当没有要删除的内容时，它说"没有什么可删除的，请返回菜单"。

List<string> Temp = new List<string>();
while (true)
{
string val;
Console.WriteLine("[L] ägg till temp-mätning: ");
Console.WriteLine("[S] kriv ut alla temperaturer och medeltemperatur");
Console.WriteLine("[T] ag bort temp-mätning");
Console.WriteLine("[A] vsluta");
Console.Write("Selection: ");
val = Console.ReadLine();
if (val == "l" || val == "L")
{
Console.WriteLine("add temperature : ");
Temp.Add(Console.ReadLine());
Console.Clear();
}
else if(val == "s" || val == "S") 
{
int index = 1;
Console.Clear();
Console.WriteLine($"Your temperatures are: ");
Temp.ForEach(x => Console.WriteLine($"{index++} - {x}"));
}
else if (val == "t" || val == "T")
{
Console.Write($"Which temp do you want to delete [index from 1 to {Temp.Count}]: ");
int deleteIndex = int.Parse(Console.ReadLine()) - 1;
Temp.RemoveAt(deleteIndex);
}
else
{
Console.WriteLine("incorrect input: ");
Console.Clear();
break;
}

Answer 1

要控制使用输入，您可以提取方法，例如

private static int ReadInteger(string title) {
while (true) {
if (!string.IsNullOrWhiteSpace(title))
Console.WriteLine(title);
if (int.TryParse(Console.ReadLine(), out int result))
return result;
Console.WriteLine("Incorrect syntax, please, try again.");
}
}

然后你可以把

val = Console
.ReadLine()
.Trim()      // Let's be nice and tolerate leading / trailing spaces, e.g. " L "
.ToUpper();
val = val.Substring(0, Math.Max(1, val.Length));
switch (val) {
case "L":
// We read valid integer, turn it to string and out to Temp
Temp.Add(ReadInteger("add temperature : ").ToString());
Console.Clear();
break;
case "T":
int deleteIndex = ReadInteger(
"$"Which temp do you want to delete [index from 1 to {Temp.Count}]: ");
if (deleteIndex >= 0 && deleteIndex < Temp.Count)
Temp.RemoveAt(deleteIndex);
else
Console.WriteLine("Index out of range");
break;
...   
}

Answer 2

在提问之前，请查看 C# 参考网站或书籍。

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/

这是您想要的代码，希望对您有所帮助：

List<string> Temp = new List<string>();
while (true)
{
menu:
string val = string.Empty;
Console.WriteLine("[L] ägg till temp-mätning: ");
Console.WriteLine("[S] kriv ut alla temperaturer och medeltemperatur");
Console.WriteLine("[T] ag bort temp-mätning");
Console.WriteLine("[A] vsluta");
Console.Write("Selection: ");
val = Console.ReadLine();
switch (val.ToLower())
{
case "l":
addTemperature:
Console.WriteLine("add temperature : ");
string temperatureInput = Console.ReadLine();
int temperatureToAddToList;
try
{
temperatureToAddToList = Convert.ToInt32(temperatureInput); //This line trys to convert string variables to integer variables. If string variable includes any character, it will throw an exception.
}
catch (Exception error) //If an exception was thrown, this code block gets activated, which will give out the message you asked for.
{
Console.Clear();
Console.WriteLine("Please enter a number instead of a string!");
goto addTemperature;
}
Temp.Add(temperatureInput.Trim());
Console.Clear();
break;
case "s":
int index = 1;
Console.Clear();
Console.WriteLine($"Your temperatures are: ");
Temp.ForEach(x => Console.WriteLine($"{index++} - {x}"));
break;
case "t":
if (Temp.Count == 0)
{
Console.Clear();
Console.WriteLine("There is nothing to delete, go back to menu.");
goto menu;
}
else
{
Console.Write($"Which temp do you want to delete [index from 1 to {Temp.Count}]: ");
int deleteIndex = int.Parse(Console.ReadLine()) - 1;
Temp.RemoveAt(deleteIndex);
break;
}
default:
Console.WriteLine("incorrect input: ");
Console.Clear();
break;
}

我已经修改并更新了我的代码示例，以更好地解决您的问题。