Calling a Form component from a child class

bob

What is the best OO practice for accessing a Form component from a child class? For example in my Form1 class I have an instance of a class MyClass. Form1 has a Label component. I'd like to change this label component from within MyClass. How can I do this nicely without breaking some OO principles. Thanks.

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

bob17y ago
Thanks for the help guys. Your solution works. Instead of making the properties public I just made a public function in Form1 that modifies the local components. This is because I want to minimize the number of Windows Forms specific calls in my Class (which has nothing to do with Windows Forms).
0
Serban Cosmin17y ago
You can make a public property that would modify that label's text. For instance, in Form1, you have : public string MyLabelText { set{ label1.Text = value; } } and from MyClass you call on the instance of Form1 the MyLabelText property, like this: myForm1.MyLabelText = someStringValue. Thus you keep the label private to your Form class and respect principles of OOP of keeping stuff as private as possible. If you decide at some time to change that label with some custom control on the form, your MyClass will not be broken as it will only access the property that you will modify from within Form1 to accomodate your new control. Hope this helps.
0
Kirtan Patel17y ago
Friend ,

Here is Explanation How i Done it ( I added comment in code to explain it :)

friend, dont forget to mark "do you like this answer" if my answer helped you :)

First on Form I taken one Label Called Label 1 and Made it Public :)

Now Code Like Below in MyClass and Form1

MyClassCode
------------------------

namespace WindowsFormsApplication8
{
    class MyClass
    {

        public void ChangeTheLabel()
        {
            //Locate the Running Intance of Form1
            Form f = Application.OpenForms["Form1"];

             //Here i can Access Label1 Because i have made it Public in Form1
            ((Form1)f).label1.Text = "Testin OO Concepts ";

        }

    }
}

Form1 Code
--------------

namespace WindowsFormsApplication8
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

       private void button1_Click(object sender, EventArgs e)
        {
            //Instantiate the MyClass
            MyClass m = new MyClass();

            //Call the Method to change the label
            m.ChangeTheLabel();
        }
    }
}

so its not breaking any oops concepts and works well .

also you can do this by defining propertiy but it can be simply done as above code :)

0