Hide and Show Second form on Button Click

Question

I want to show another form(Form2) with button click. Basically When the button is clicked in Form1, another form(Form2) should show, this should not hide the Form1 though and should change the button text to "Hide Progress" in Form1. And when this button is clicked again the Form2 should hide and the text in button should change to "Show Progress".

Below is my effort to make this work. When I clicked the Show Progress Button, it brings the Form2 and changes the text in button as well. But when I clicked the button again instead of hiding the Form2, it opens another instance of Form2.

Probably reason behind is that, the bool value is not saved.

Here is my code for button event handler.

public partial class Main : Form
    {
       public string output_green, output_grey, output_blue, output_black;
       public bool visible;
 private void button1_Click(object sender, EventArgs e)
        {

            output progressWindow = new output();

            if (visible == false)
            {
                progressWindow.Show();
                button1.Text = "Hide Progress";
                visible = true;
            }

            else
            {
                progressWindow.Show();
                button1.Text = "Show Progress";
                visible = false;

            }

        }
}

How can I achieve that I need to.

Answer 1

Problem:

Each time you click button1 a new progressWindow has been initialized.

Also you are using progressWindow.Show() instead of Hide() in else part.

Solution:

Declare progressWindow out of button1_Click. And then initialize it from button1_Click. Now it will be initialized only once (using if).

output progressWindow = null;
private void button1_Click(object sender, EventArgs e)
{            
        if(progressWindow == null)
            progressWindow = new output();
        if (button1.Text == "Show Progress")
        {
            progressWindow.Show();
            button1.Text = "Hide Progress";
        }
        else
        {
            progressWindow.Hide();
            button1.Text = "Show Progress";
        }
    }
}

Answer 2

For a shorter solution where the progress window's lifetime persists with the main form :

    output progressWindow = new output();
    private void button1_Click(object sender, EventArgs e)
    {
        progressWindow.Visible = !progressWindow.Visible;
        button1.Text = (progressWindow.Visible) ? "Hide Progress" : "Show Progress";
    }

Here you get rid of the need for the extra boolean since the progress form itself is fully capable of telling you whether it is visible or not.

Answer 3

  // Creates a single instance only it it is request.
  private Output ProgressWindow
    {
      get 
          {
              return progressWindow?? (progressWindow= new Output(){Visible = false};
          }
    }

   private Output progressWindow;

    private void button1_Click(object sender, EventArgs e)
    {            
         ProgressWindow.Visible = !ProgressWindow.Visible;
         button1.Text = (ProgressWindow.Visible) ? "Hide Progress" : "Show Progress";

        }
    }