Why is MdiParent null?

Question

0.00/5 (No votes)

See more:

Form1 f1=new Form1();
f1 is the main form
f1 is an Mdi Container;

Form2 f2=new Form2();
f2.MdiParent=this;
f2.show();

Now, in constructor of the f2 I have:

Form1 f1=(Form1)this.MdiParent; // ERROR

But MdiParent is NULL...

Why?

Thank you...

Posted 15-May-13 23:38pm

Luci C

Updated 15-May-13 23:43pm

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2013-05-15T23:44:00

Solution 1

Because it is in the constructor. Look at your code:

C#

Form2 f2=new Form2();
f2.MdiParent=this;

The first line of the two calls the constructor for Form2, before the second instruction is executed.

Consider moving your code from the constructor into the Form2.Load or Form2.Shown events.

[edit]Typo: "Lein" for "Line" - OriginalGriff[/edit]

Posted 15-May-13 23:44pm

OriginalGriff

Updated 15-May-13 23:45pm

v2

Comments

Luci C 16-May-13 6:03am

You're right...Thank you!

OriginalGriff 16-May-13 6:06am

:laugh: You're welcome!

ductuan_itpro 12-Jan-16 23:54pm

Good solution!
I define a global variable _parent in Form2. Set its value at Form2_Load.
Then I can use it anywhere.