using System;

public class Program

{

    public static void Main()

    {

        var str = DateTime.Now.ToString();

        var dt = ConvertTo<DateTime>("fieldName", typeof(string), str);

        Console.WriteLine(dt);

    }

    private static T ConvertTo<T>(string fieldName, Type fieldType, object @object)

    {

        if (fieldType.IsAssignableFrom(typeof(T)))

        {

            return (T)@object;

        }

        if (fieldType.IsAssignableFrom(typeof(DateTime)))

        {

            var value = (DateTime)@object;          

            return value != default(DateTime) ? (T)@object : default(T);

        }

        if (fieldType.IsAssignableFrom(typeof(int)))

        {

            var value = (int)@object;           

            return value != default(int) ? (T)@object : default(T);

        }

​

        throw new InvalidOperationException(string.Format("{0} type is not assignable from {1}.", fieldName, typeof(T)));

    }

}