Question

I have two Froms (Form1, Form2) and I’m getting this Error when I try to call a public function of Form2 from the Form1 class.

Error 1 ‘System.Windows.Forms.Form’ does not contain a definition for ‘getText1’ and no extension method ‘getText1’ accepting a first argument of type ‘System.Windows.Forms.Form’ could be found (are you missing a using directive or an assembly reference?) C:\Users…\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs 24 17 WindowsFormsApplication1.

  public partial class Form1 : Form
  {

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form gen = new Form2();
        gen.ShowDialog();
        gen.getText1(); // I'm getting the error here !!!
    }
}

public partial class Form2 : Form
{
    public string Text1;

    public Form2()
    {
        InitializeComponent();
    }

    public string getText1()
    {
        return Text1;
    }

    public void setText1(string txt)
    {
        Text1 = txt;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.setText1(txt1.Text);
        this.Close();
    }
}

Any ideas? Thanks for your help.

Answer 1

The compile-time type of gen is currently just Form. Change that and it should be fine:

Form2 gen = new Form2();
gen.ShowDialog();
gen.getText1();

Note that this has nothing to do with GUIs in particular – it’s just normal C#. If you’re just starting out with C#, I suggest that you learn it with console apps instead – there are far fewer oddities that way, and you can learn one thing at a time.

I’d recommend that you start following .NET naming conventions, use properties as appropriate, and dispose of forms too:

using (Form2 gen = new Form2())
{
    gen.ShowDialog();
    string text = gen.Text1;
}

(Even then, Text1 isn’t a very descriptive name…)