String format template as parameter

Question

I'm beginer in C#. Now I have next task: In method I get template and arguments and I have to return formated string.

For example:

template = "Hello, {name}!"

name = "Bob"

So result must be a string -> Hello, Bob!

public static string GetHelloGreeting(string template, string name)
{
    return string.Format(template, name);
}

Answer 1

String.Format expects an index in the braces. You want to pass the name in it, so you can replace it with the actual name value. I'd suggest to use String.Replace:

public static string GetHelloGreeting(string template, string name)
{
    return template.Replace("{name}", name);
}

You could provide a method which is more reusable. For example:

public static string ReplaceAll(string template, params (string key, string value)[] replacements)
{
    foreach (var kv in replacements)
    {
        template = template.Replace("{"+ kv.key + "}", kv.value);
    }

    return template;
}

Your example:

string res = ReplaceAll("Hello, {name}!", ("name", "Bob"));

but also possible with multiple parameters:

string res = ReplaceAll("Hello, {name}! Now it's {time}", ("name", "Bob"), ("time", DateTime.Now.ToString("HH:mm")));