如何将一个表单的实例传递给另一个表单

Question

I have a form called form1 with controls which are created during run-time.

When I press a button on the Form another Form loads called combat and form1 is hidden so that only 1 form ( combat ) is visible.

When I press a button on combat I want my form1 form the be shown. However I can't access it.

Here is what I've tried:

 private void combatBtn_Click(object sender, EventArgs e)
    {
        Form combat = new Combat(this);
        this.Hide();
        combat.Show();

    }

public partial class Combat : Form
 {

    public Combat(Form form)
    {
        InitializeComponent();
        form.Show();


    }

    private void button1_Click(object sender, EventArgs e)
    {
        form.Show();
    }
}

Answer 1

您需要将父表单存储在一个字段中，以便可以在构造函数之外访问它。

Answer 2

public partial class Combat : Form
{

    private form1 form;    // Or whatever class you form1 is supposed to be

    public Combat(Form form)
    {
        InitializeComponent();
        this.form = form;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        form.Show();
    }
}

Answer 3

It's generally not advisable to pass an instance of a parent form to a child. In this case (as is often true) the code is actually simpler when you don't:

private void combatBtn_Click(object sender, EventArgs e)
{
    Form combat = new Combat();
    this.Hide();
    combat.ShowDialog();
    this.Show();
}

If you need to show the parent form before the child form is closed then you can do so through events:

in Combat add:

public event Action MyEvent; //TODO rename to a meaningful name

Fire the event in the button click handler:

private void button1_Click(object sender, EventArgs e)
{
    MyEvent();
}

And then have your main form add a handler to the event:

private void combatBtn_Click(object sender, EventArgs e)
{
    Combat combat = new Combat();
    this.Hide();
    combat.MyEvent += () => this.Show();
    combat.Show();
}