Creating a class object in C#

Question

I am trying to create an object of a class, but it doesn't seem to work, I can't help but think I am looking at this from a JAVA perspective:

 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            PortChecks PortCheckObject = new PortChecks();

        }

private void testCheck_Click(object sender, EventArgs e)
        {
            PortCheckObject.MyMethod();
        }

I can error when using the PortCheckObject to call my method MyMethod

(PortChecks is the class name)

Your PortCheckObject is a local variable in the contructor of Form1 that you cannot access from testCheck_Click. This would be the same even in Java. — Tim Schmelter
– Tim Schmelter, Commented Sep 12, 2011 at 19:56

msarchet · Accepted Answer · 2011-09-12 19:54:28Z

9

It's because it's outside of the scope of testCheck_Click

public partial class Form1 : Form
{
    PortChecks PortCheckObject = new PortChecks();

    public Form1()
    {
        InitializeComponent();
    }

    private void testCheck_Click(object sender, EventArgs e)
    {
        PortCheckObject.MyMethod();
    }
}

answered Sep 12, 2011 at 19:54

msarchet

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1 Comment

James Over a year ago

Thank you, should have seen thar,, ^ ^

Sergey Metlov · Accepted Answer · 2011-09-12 19:54:38Z

3

PortChecks PortCheckObject in Form1 constructor is a local variable.
Put its declaration as a private field in Form1 class.

public partial class Form1 : Form
{
    private PortChecks PortCheckObject = new PortChecks();

    public Form1()
    {
        InitializeComponent();
    }

    private void testCheck_Click(object sender, EventArgs e)
    {
        PortCheckObject.MyMethod();
    }
}

answered Sep 12, 2011 at 19:54

Sergey Metlov

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Comments

Bruno Arueira · Accepted Answer · 2011-09-12 19:57:06Z

2

@James,

You need a class property with the name 'PortCheckObject' and can be possible to access in other parts of the class.

public partial class Form1 : Form
{
    private PortChecks PortCheckObject;

    public Form1()
    {
        InitializeComponent();

        PortCheckObject = new PortChecks();
    }

    private void testCheck_Click(object sender, EventArgs e)
    {
        PortCheckObject.MyMethod();
    }
}

answered Sep 12, 2011 at 19:57

Bruno Arueira

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Comments

Max · Accepted Answer · 2011-09-12 19:57:52Z

1

This is a general scope issue, not a Java v.s. C# issue (as your code wouldn't work in Java either). PortCheckObject is in Form1()'s scope, not testCheck_Click's scope. Try the following:

public partial class Form1 : Form
{
    private PortChecks PortCheckObject;

    public Form1()
    {
        InitializeComponent();

        PortCheckObject = new PortChecks();

    }

private void testCheck_Click(object sender, EventArgs e)
    {
        PortCheckObject.MyMethod();
    }

answered Sep 12, 2011 at 19:57

Max

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Comments

Kevek · Accepted Answer · 2011-09-12 19:56:15Z

0

This is an instance of a scope problem. You do not have scope in your testCheck_Click method. Make the following change and it should work:

public partial class Form1 : Form
{
    private PortChecks MyPortCheck {get; set;}

    public Form1()
    {
        InitializeComponent();
        MyPortCheck = new PortChecks();
    }

    private void testCheck_Click(object sender, EventArgs e)
    {
        MyPortCheck .MyMethod();
    }

...
}

answered Sep 12, 2011 at 19:56

Kevek

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