CODEWITHSUNDEEP
c#winformslinqmdichildmdiparent
greg dorian
greg dorian

Reputation: 134

Close all MDI child windows using Linq

I'm trying to use the following loop

foreach (Form frm in this.MdiChildren)
{
    frm.Close();
}

and transcribe it into a Linq expression like so:

this.MdiParent.MdiChildren.OfType<Form>().ToList().ForEach(x => x.Close());

but this line shows me a NullReferenceException "Object reference not set to an instance of an object"

What am I doing wrong? I am a newbie in Linq.

Upvotes: 3

Views: 4504

Answers (1)

Hanlet Esca&#241;o
Hanlet Esca&#241;o

Reputation: 17380

Try this:

this.MdiChildren.OfType<Form>().ToList().ForEach(x => x.Close());

Unless you are trying that code from one of the children, in which case you try your code

this.MdiParent.MdiChildren.OfType<Form>().ToList().ForEach(x => x.Close());

and it should also work.

Upvotes: 5

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