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The empty string passes from one form to another in Winforms

 2 years ago
source link: https://www.codesd.com/item/the-empty-string-passes-from-one-form-to-another-in-winforms.html
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The empty string passes from one form to another in Winforms

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I have following problem: I have a Form1 where I open a second Form2 from it. Now I have a save Button in Form2 where entries from Textboxes are saved to a csv file. But I want to save some entries from Form1 too. The Textbox entries from Form2 are getting saved but entries from Form1 are empty strings. Following code:

In Form1:

public void showInputToolStripMenuItem_Click(object sender, EventArgs e)
    {
        Form2 form2 = new Form2(this);
        form2.Show();
    }

to open the second Form via the first one and functions to grab the entries from the Form1 Textboxes:

    public String getLocation()
    {
        return LocationBox.Text;
    }

    public String getFilesLoc()
    {
        return FilesLocation.Text;
    }

In Form2 I have the following:

    private Form1 m_form = null;

    public Form2(Form1 f)
    {
        InitializeComponent();
        m_form = f;
    }

and then the function to grab the entries and save them:

     private void button1_Click(object sender, EventArgs e)
    {
        Form1 form1 = new Form1();
        proc.setParams(form1.getLocation(),getFilesLoc());
        proc.saveCurrentSettings();
    }

I left the other parameters out. So entries from Form2 are read correctly but the ones from Form1 are just an empty string (""). What can I do?

In the click handler, you're creating a new Form1 here:

Form1 form1 = new Form1();

That will have empty values - but you want the value from the existing form which you kept a reference to in your constructor - so use it!

private void button1_Click(object sender, EventArgs e)
{
    proc.setParams(m_form.getLocation(), m_form.getFilesLoc());
    proc.saveCurrentSettings();
}

(I'd strongly advise you to start following .NET naming conventions, quite possibly turning those get methods into properties, and also considering passing the values into your Form2 constructor instead of the Form1 reference itself. It depends on whether you need to "see" any changes made to Form1 after the construction of Form2.)


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