我如何使C＃忽略字母大小写

Question

Here I have some simple C# code;

Console.WriteLine("Enter Name");
var name = Console.ReadLine();
if (name == "ashley")
{
    Console.WriteLine("You entered: " + name);
}
Console.Read();`

If the user enters ashley it will display "You entered ashley". However if the user enters Ashley or AsHlEy it won't work. What do I need to add to this or how to format so it will ignore the case?

Answer 1

String.Compare takes a boolean parameter which allows you to ignore casing during comparison:

Console.WriteLine("Enter Name");
var name = Console.ReadLine();

if (String.Compare(name, "ashley", true) == 0)
{
    Console.WriteLine("You entered: " + name);
}

Console.Read();

Answer 2

Use string.Equals with an appropriate StringComparison

if (string.Equals(name, "ashley", StringComparison.CurrentCultureIgnoreCase))
{
   ...
}

If you know that the variable is not null you can also use

if (name.Equals("ashley", StringComparison.CurrentCultureIgnoreCase))
{
   ...
}

To answer your question in the comments, a do-while loop can be used to loop until the question is answered correctly. The below will loop until the user enters something other than ashley .

string name;
do
{
     Console.WriteLine("Enter Name");
     name = Console.ReadLine();
}
while (string.Equals(name, "ashley", StringComparison.CurrentCultureIgnoreCase));

You could combine this with a guard variable if you want different messaging:

string name;
bool nameIsCorrect = false;
do
{
     Console.WriteLine("Enter Name");
     name = Console.ReadLine();

     nameIsAshley = string.Equals(name, "ashley", StringComparison.CurrentCultureIgnoreCase);

     if (nameIsAshley)
     {
        Console.WriteLine("Stop entering 'ashley'");
     }
}
while (!nameIsAshley);

Answer 3

change this:

if (name == "ashley")

to this:

if (name.ToLower() == "ashley")

Answer 4

Use ToLower like this:

Console.WriteLine("Enter Name");
var name = Console.ReadLine();
if (name.ToLower() == "ashley")
{
    Console.WriteLine("You entered: " + name);
}
Console.Read();`

Answer 5

You can use the String.ToLower method

your test would be: if (name.ToLower() == "ashley")