Return values from a form

Question

Hi ,

Which is the best technique to return values from a form and use that in another form . like using a variable or some other way . for example , i have a form with a textbox which returns a value . i want to use that value in the textbox of other form . can you please share how to do it in the an efficient manner .

Answer 1

Hi @Shaifali jain , Welcome to Microsoft Q&A,

There are indeed multiple ways to get the value in a subform,

For example, use public properties or use delegates.

Here's how to use public properties:

Form1

private void button1_Click(object sender, EventArgs e)
{
    Form2 form2 = new Form2();
    form2.ShowDialog();
    MessageBox.Show("The return value is: " + form2.returnString);
}

Form2

public partial class Form2 : Form
{
    public string returnString;
    public Form2()
    {
        InitializeComponent();

    }

    private void textBox1_KeyDown(object sender, KeyEventArgs e)
    {
        returnString = textBox1.Text;
    }
}

Here's how to use delegation: Add delegates and events to child windows. Set up the child window to call the above event and pass the string that needs to be passed to the event to the event. Add a method to display the returned information in the main window, the same as participating in the MyAccountDelegate delegation. Call the event in the main window.

Form1:

private void button1_Click(object sender, EventArgs e)
{
    Form2 form2 = new Form2();
    form2.MyAccountEvent += new Form2.MyAccountDelegate(DisplayMyAccount);
    form2.ShowDialog();
    MessageBox.Show("The return value is: " + returnString);
}
private string returnString;
private void DisplayMyAccount(string account)
{
    returnString = account;
}

Form2:

public partial class Form2 : Form
{
    public delegate void MyAccountDelegate(string account);
    public event MyAccountDelegate MyAccountEvent;
    public Form2()
    {
        InitializeComponent();
    }

    private void textBox1_KeyDown(object sender, KeyEventArgs e)
    {
        if (textBox1.Text.Length > 0)
        {
            MyAccountEvent(textBox1.Text);//Add account information
        }
    }
}

Best Regards,

Jiale

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Answer 2

You can expose the values you want to exchange as properties of the form. Once the form closes, you still have a reference to the form in the parent/calling form and you can get the values from the properties.