opening and closing forms

j_sen21

19y3.4kVisual Basic .NET

Hello,

I can not get the second form to completly close.

On form 1, I perform

if (m_FrmIdentify == null)

{

nFrmIdentify = new frmIdentify();

}

if (m_FrmIdentify.Visible == true)

{

FrmIdentify.Loadss();

}

else

{

mFrmIdentify.Show();

}

In form 2, on close

I tried callinig this.close() and this.hide(); Neiter of which make the call above mFrmIdentify == null

so that I can reopen the same form again.

THanks.

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sam19y ago

Hi,

I think your problems is that by default when you close a form the form's Dispose() method is called. This causes an exception when methods of the form are called but doesn't make the varibale to the form == null.

A possible solution is to handle the 2nd form's FormClosing event like so:

private void Form2_FormClosing(object sender, FormClosingEventArgs e)

{

e.Cancel = true;

this.Hide();

}

Hope this helps,

Sam
j_sen2119y ago
Sorry I reposted here, I just got sloppy. Its one form. Loadss is just a random function that it performs if the form has already been created and is visible.

//does this check because if its already created and open, then it wont create another form

I cant create a new form everytime, only when its not already created and open.

if (mFrmIdentify == null)
{

//creates a new form if one is not open.

mFrmIdentify = new frmIdentify();

}
else
{

//When a user interacts with the first form while form mFrmIdentify is already open it comes in here.

if (mFrmIdentify.Visible)
{

//just a function that it calls if the form is open

mFrmIdentify.L oadss();
}
else
{

mFrmIdentify.Show();
}

}

Thanks.
Jan Montano19y ago
I'm a little bit confused with the code. You mentioned you have 2 forms, but you introduced 3 variables, namely m_FrmIdentify, nFrmIdentify and mFrmIdentify.

You have a frmIdentify Class but you also called FrmIdentify.Loadss() which I'm guessing FrmIdentify is another class?

What's the definition/name of your form1 & form2? I'm assuming form2 is m_FrmIdentify?.

You could try to just Hide m_FrmIdentify instead of closing it then check if it is visible or not. Here's my suggestion...

if (m_FrmIdentify == null)
{
//nFrmIdentify = new frmIdentify();
}
else
{
if (m_FrmIdentify.Visible)
{
//FrmIdentify.Loadss();
}
else
{
//mFrmIdentify.Show();
}
}
j_sen2119y ago
No, it will only stay visible as long a user doesnt close it (mFrmIdentiy.close())

Because a user can still change things on form 1, mFrmIdentiy updates because it is still open (mFrmIdentify != null) and visible. Otherwise if mFrmIdentity is not open, it opens it.

Thanks.

I guess the only thing that does work is this line if (mFrmIdentify == null) in form 1, then do something.

It works the first time when mFrmIdentify form hasnt been opened yet. But then I close mFrmIdentify, and then try to reload the form again, it thinks that mFrmIdentify is not null anymore. I need to null mFrmIdentify from the closing event or other code that performs the same operation. I was thinking of writing a integer to a file to say the form is open or closed.
Richard Blythe19y ago
I'm not sure what your trying to accomplish by all this. Are you trying to make a form that will always stay visible? If a better way would be to trap the form's "FormClosing" event and set the cancel property to true. e.Cancel = true;
If this hasn't answered your question, please write back.

Cheers!
Richard