extend TryParse for All DataType

Question

I write a function to check data type int32

 public static Int32? ParseInt32(this string text)
        {
            Int32 result;
            if (!Int32.TryParse(text, out result))
                return null;
            return result;
        }

How do I extend this function that supports all data types???

thanks.

Answer 1

How about something like this:

public static T? TryParse<T> (this string text) where T: struct
{
    T? result = null;

    if (!string.IsNullOrEmpty(text))
    {
        try
        {
            result = (T?) Convert.ChangeType(text, typeof (T));
        }
        catch (InvalidCastException) {}
        catch (FormatException) {}
        catch (OverflowException) {}
    }

    return result;
}

You would then call it like this:

int? myInt = "100".TryParse<int>();

or

DateTime? myDate = "2001-01-01T23.00.00".TryParse<DateTime>();

Answer 2

Here's a minimal working example:

using System;

namespace ConsoleApplication1
{
    struct Test
    {
        // No TryParse method here!
    }

    static class Program
    {
        static void Main(string[] args)
        {
            var invalidTest = "12345".ParseTo<DateTime>();
            var validTest = "12345".ParseTo<int>();
            var veryInvalidTest = "12345".ParseTo<Test>();

            Console.WriteLine(!invalidTest.HasValue ? "<null>" : invalidTest.Value.ToString());
            Console.WriteLine(!validTest.HasValue ? "<null>" : validTest.Value.ToString());
        }

        public static T? ParseTo<T>(this string test) where T : struct
        {
            var method = typeof(T).GetMethod("TryParse", new Type[] { typeof(string), typeof(T).MakeByRefType() });

            if (method == null)
                throw new Exception(); // or return null or whatever

            var parameters = new object[] { test, null };

            if ((bool)method.Invoke(null, parameters))
            {
                return (T)parameters[1];
            }
            else
                return null;
        }
    }
}

Answer 3

Well for that you can make use of Generics but in the method body you need to make use of the type to parse it out in perticular data type.

you can check this : Using Generic Extension Methods