Question

I have windows form with one textbox(Pname) and one button.
I have one class by name Player with no constructor.

When user enters text inside textbox (e.g. John) and clicks button, system will create and an instance of a class Player with name of an object as John.

Answer 1

Your question is not very clear but I interpret that you want your Player class to store a name, that will be supplied by the user.

In that case, you need to add a property of string type named Name to your Player class, and when the user clicks the button, you create a new instance of Player (you can even if you don’t explicitly define a constructor), and set the property from the value of the textbox. For example, you would define the class like this:

class Player
{
    public string Name {get;set;}
    //Other members (if any)
}

and in the event handler for the button click (assuming your textbox is named theTextBox):

var player = new Player();
player.Name = theTextBox.Text;
//Do whatever you need with the instance of Player