C# - Return variable from child window to parent window in WPF

Question

I have a main window called form1. in form1 I have a button, when it is pressed it will open form2 (form2.ShowDialog()). In form2 I have a button called \"Check\". When the

Answer 1

This could be accomplished in several ways. The method Servy posted is quite good and will accomplish what you need. I would prefer to see the Action passed as a parameter to the constructor and named callback so it's clear what it is used for, but that's just a preference thing.

The other method that is pretty good at getting this done is via Messaging. The MVVMLight Toolkit provides a great little feature in it for accomplishing tasks such as this.

Step 1: create a strongly typed Message:

public class MyMessage : MessageBase
{
    //Message payload implementation goes here by declaring properties, etc...
}

Step 2: Determine where, and when to publish that message.

public class PublishMessage
{
    public PublishMessage(){
    }

    public void MyMethod()
    {
        //do something in this method, then send message:
        Messenger.Default.Send(new MyMessage() { /*initialize payload here */ });
    }
}

Setp 3: Now that you are sending the message, you need to be able to receive that message:

public class MessageReceiver
{
    public MessageReceiver()
    {
        Messenger.Default.Register(this, message => Foo(message));
    }

    public void Foo(MyMessage message)
    {
        //do stuff
    }
}