Type.dib

#!markdown

# **Type** data type - how to create it

#!csharp

//System.Type

//Using typeof operator
var typeInfo = typeof(string);
display(typeInfo);

//Using object.GetType() method
string s = "Text";
typeInfo = s.GetType();
display(typeInfo);

//Using Type.GetType static method
typeInfo = Type.GetType("System.String");
display(typeInfo);

//Generics
typeInfo = typeof(List<string>);
display(typeInfo);

#!markdown

# **Type** data type - properties

#!csharp

var typeInfo = typeof(Type);

var properties = typeInfo.GetProperties().Select(p => new { p.Name, p.PropertyType });
display(properties);

#!csharp

class Person
{
    public string Name { get; set;}
    public string LastName { get; set; }
    public int TestProp {get ;set;}
}

var typeInfo = typeof(Person);

var properties = typeInfo.GetProperties().Select(p => new { p.Name, p.PropertyType });
display(properties);

#!markdown

# **Type** data type - methods

#!csharp

var typeInfo = typeof(Type);

var methods = typeInfo.GetMethods().Select(m => new { m.Name, ParamCount = m.GetParameters().Count(), m.ReturnType });
display(methods);

#!csharp

class Person
{
    public string Name { get; set;}

    public void M1(int a, int b) {}
    public void M1(int a, int b, int c) {}
    public int M2(int a) => a;
}

var typeInfo = typeof(Person);
var methods = typeInfo.GetMethods().Select(m => new { m.Name, ParamCount = m.GetParameters().Count(), m.ReturnType });
display(methods);

#!markdown

# **Type** data type - how to use (for properties)

#!csharp

class Person
{
    public string Name { get; set;}
    public string LastName { get; set; }
    public int Age { get; set;}
}

var person = new Person() { Name = "John", LastName = "Johnson"};
var typeInfo = typeof(Person);

foreach (var property in typeInfo.GetProperties())
{
    var value = property.GetValue(person);
    Console.WriteLine($"{property.Name}: {value}");
}

var prop = typeInfo.GetProperty("LastName");
prop.SetValue(person, "Carl");

display(person);

#!markdown

# **Type** data type - how to use (for methods)

#!csharp

class Person
{
    public string Name { get; set;}
    public string LastName { get; set; }

    public string GetDisplayName(string locale)
    {
        if (locale == "lt-LT")
        {
            return $"{Name} {LastName}";
        }
        return $"{LastName}, {Name}";
    }
}

var person = new Person() { Name = "John", LastName = "Johnson"};
var typeInfo = typeof(Person);

var method = typeInfo.GetMethods().FirstOrDefault(m => m.Name == "GetDisplayName");
var result = method.Invoke(person, new[] { "lt-LT" }); //var result = person.GetDisplayName("lt-LT")
Console.WriteLine(result);
result = method.Invoke(person, new[] { "en-US" });
Console.WriteLine(result);

#!markdown

# **Type** data type - how to use (for constructor)

#!csharp

class Person
{
    public string Name { get; set;}
    public string LastName { get; set; }

    public Person(string name, string lastName)
    {
        Name = name;
        LastName = lastName;
    }
}

var typeInfo = typeof(Person);
var constructor = typeInfo.GetConstructors().FirstOrDefault();
var person = constructor.Invoke(new []{ "John", "Johnson" }) as Person;

display(person);

person = constructor.Invoke(new []{ "John", "Smith" }) as Person;
display(person);