How to make mdichild load at the center of mdiparent window

问题

HI all,

I have this code in which the window property of making child window load at the center of mdiparent.

        Form2 f = new Form2();

        f.MdiParent = this;

        //center screen is working.

        //f.StartPosition = FormStartPosition.CenterScreen;

        f.StartPosition = FormStartPosition.CenterParent;

but instead of making the child window pop at the center it loads at the left side. Can anyone help me on this. Please refer the screenshot below.

I have even tried doing the same in vb. Even there i get the same error. I think the property of FormStartPosition.CenterParent is dummy.

alt text http://img13.imageshack.us/img13/7003/errorprb.jpg

回答1:

I experimented a bit with this, and first came to the same solution as Patrick. But I was bugged by the following statement in the documentation of the StartPosition property:

You can also position the form to display in the center of the screen or in the center of its parent form for forms such as multiple-document interface (MDI) child forms.

So, I decided that there must be a way. And there is, though I don't find it all intuitive: set the StartPosition to CenterScreen (not CenterParent):

MdiChildUI form = new MdiChildUI();
form.MdiParent = this;
form.StartPosition = FormStartPosition.CenterScreen;
form.Show();

Of course, you can also set it in the designer instead of in code.

回答2:

Setting start position as center screen works perfect for me.

回答3:

I tried showing the child with the MDI container form as owner, but caused an exception for me. You could manually set the location before showing the child as follows:

Form2 f = new Form2();
f.MdiParent = this;
f.StartPosition = FormStartPosition.Manual;
f.Location = new Point((this.ClientSize.Width - f.Width) / 2,
                       (this.ClientSize.Height - f.Height) / 2);
f.Show();

EDIT:

f.StartPosition = FormStartPosition.CenterScreen;

is the correct way to center an mdichild on its parent form.

回答4:

A form has an MdiParent property and a Parent property.

Please notice that an MdiParent IS NOT the parent of MdiChild form.

It is, its MdiParent;

So CenterToParent Method is meaningless for these types of forms.

You can see the functionality of CenterToParent Method when you program for multiple monitors application, or when you host a form inside another form by setting its Toplevel property to false, and setting its Parent property to another form.

Good Luck,

Aram Afsar

来源：https://stackoverflow.com/questions/1228120/how-to-make-mdichild-load-at-the-center-of-mdiparent-window

标签

mdi