CODEWITHSUNDEEP
c#forms
Patryk
Patryk

Reputation: 3152

New window form in a c# program

I'm trying to open a new window form on a button click

In main program's constructor I've got:

form_targeting = new Targeting();

In button1_Click(...) there is:

form_targeting.Show();

and ofc in main program's fields there's

public static Targeting form_targeting;

When opening first time, It works correctly. After closing 2nd window and pressing the button in a 1st window again, I get error:

Cannot access a disposed object. Object name: 'Targeting'.

I've added that into Targeting class but it still doesn't work:

        private void Targeting_FormClosing(Object sender, FormClosingEventArgs e)
            {
                this.Hide();
                e.Cancel = true;
            }

It works now, I had to write completely the same but using designer :p thanks guys :)

Upvotes: 0

Views: 141

Answers (3)

Romil Kumar Jain
Romil Kumar Jain

Reputation: 20745

The below code means, you are initializing a instance of Targeting from.

 form_targeting = new Targeting();

Once you show the form using following code form_targeting.Show(); and close the form by clicking on the cross button or in any way. The memory initialize to form_targeting variable in first form is get freed.

So second time, you try to open same form, it raises error.

Upvotes: 1

Marek Dzikiewicz
Marek Dzikiewicz

Reputation: 2884

Closing the form calls Dispose on it. You need to write a handler for the FormClosing event. In that event handler call Hide on your form instance and set e.Cancel = true so that the form is not closed.

Upvotes: 1

Mitja Bonca
Mitja Bonca

Reputation: 4546

Put the code into button click event.

button1_Click(...)
{
   form_targeting = new Targeting();
   form_targeting.Show();
}

End close form by 

form_targeting.Close();

Upvotes: 2

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