[webwired]

Hey everyone... So it looks like I've completed all of the operational code of my duplicate file remover application that I was building for practice... There's just one thing though that I can't seem to iron out...

There is the MainForm (Form1), then it opens up a second form with a DataGridView on it ==> after you select the items you want to delete on the DataGridView ==> You click the Delete button ==> After you click the Delete button and it does its job, a MessageBox pops up to let you know that it has completed its tasks...

The problem is that after I click OK on the popup MessageBox, and after it Closes the form with the DataGridView on it, I can't get it to bring the MainForm back to focus, it gets hidden away on the taskbar...

I've tried these, but they didn't work either...

MainForm myMainForm = new MainForm();
myMainForm.Activate();
myMainForm.BringToFront();

[tlhIn`toq]

Have form 1 subscribe to form2's .FormClosed event.

When that is raised, then have form1 bring itself into focus. This puts the responsibility where it belongs, on to Form1

[webwired]

That's some new stuff to me, so it'll take me a while to figure it out, but I'll post back the code once I have it in the bag... (I hope)

[RexGrammer]

A hint to get you pointed in the right way:

Quick and easy custom events

Oh and use the .Show() method to show the form and when you need to hide it use .Hide()...

[webwired]

Yeah, that looks like some good stuff... When it comes to Event Handlers, especially Custom ones, especially in C#, I can use all the material I can find.

[webwired]

So get this, I'm working on this... (Mind you, my almost complete application) ... when all of a sudden, I hit the Debug button to try out my latest code adjustment and some crazy Exception regarding the Database Entity makes everything come to a screeching halt...

I tried undoing everything that I had done, (with the whole Event Closing thing) even though I didn't do anything with LINQ or the Database Entity... but it keeps throwing this very unhelpful error...

On this line:
public Database1Entities() : base("name=Database1Entities", "Database1Entities")

I get this error now when I attempt to Debug:
An unhandled exception of type 'System.StackOverflowException' occurred in mscorlib.dll

That make any sense to you guys?

[tlhIn`toq]

There is no special event creation. You just use the events that already exist. Just like subscribing to a .Click event of a Button.

Most of what you need to do Visual Studio will even fill in for you:

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• 

[webwired]

Well I was able to find out what I had done to create the problem, apparently in tempting fate with messing with Custom Events, I called a function recursively over and over again

[webwired]

I really am trying to get a handle on this Subscribing to Events...

So on my MainForm I put the following:

        public MainForm()
        {
            InitializeComponent();
            SelectionForm newSelectionForm = new SelectionForm();
            newSelectionForm.FormClosed += new FormClosedEventHandler(newSelectionForm.SelectionForm_FormClosed);
        }
        void SelectionForm_FormClosed(object sender, EventArgs e)
        {
            this.Focus();
        }

And on the secondary form I put the following:

        public void SelectionForm_FormClosed(object sender, FormClosedEventArgs e)
        {

        }

Obviously I'm not getting it am I? Please, a pointer back in the right direction?

[tlhIn`toq]

The first part is fine.

The second part is unneeded. You don't have to do anything in the selection form when it closes. Just closing it will raise the "FormClosed" event. That's built-in to the form object.

Again, this is just like subscribing to a button click. When a button is clicked you don't have to go into the buttons code to do anything. You just react to it. Same here. When the form is closed you don't have to go into that form's code. You just react to it, in the Form1, by having form 1 tell itself to take focus.

[webwired]

tlhIn`toq, on 03 January 2012 - 12:01 PM, said:

The first part is fine.

The second part is unneeded. You don't have to do anything in the selection form when it closes. Just closing it will raise the "FormClosed" event. That's built-in to the form object.

Again, this is just like subscribing to a button click. When a button is clicked you don't have to go into the buttons code to do anything. You just react to it. Same here. When the form is closed you don't have to go into that form's code. You just react to it, in the Form1, by having form 1 tell itself to take focus.

Yeah, I didn't see much sense in having an empty Event, but the problem is, if I delete the Event on the secondary form, then on my MainForm, it doesn't see the Event on the secondary form, obviously, therefore won't allow me to put the Event Handler on the MainForm... So I must be doing something wrong, because even when I did have the empty Event Handler on the secondary form, it didn't bring the MainForm back up into focus upon closing...

[tlhIn`toq]

Give me a few minutes to assemble a small demo project to attach for you

[tlhIn`toq]

Button names should be obvious looking at the code below.

Code for MainForm

Spoiler

namespace SimpleTwoFormsDemo
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;

    public partial class MainForm : Form
    {
        #region Constructors

        public MainForm()
        {
            InitializeComponent();
        }

        #endregion Constructors

        #region Methods

        private void btnOpenSecondaryForm_Click(object sender, EventArgs e)
        {
            var sf = new SecondaryForm();
            sf.Show();
            sf.Location = new Point(this.Location.X + sf.Width + 5, this.Location.Y); // Have it not overlap the MainForm
            sf.CustomEventOne += sf_CustomEventOne;
            sf.CustomEventTwo += sf_CustomEventTwo;
            sf.FormClosed += sf_FormClosed;
        }

        void sf_CustomEventOne(object sender, EventArgs e)
        {
            MessageBox.Show("The First event was raised.", "1st Event");
        }

        void sf_CustomEventTwo(object sender, EventArgs e)
        {
            MessageBox.Show("The Second event was raised.", "2nd Event");
        }

        void sf_FormClosed(object sender, FormClosedEventArgs e)
        {
            MessageBox.Show("The secondary form was closed", "2nd form closed");
            this.Focus();
        }

        #endregion Methods
    }
}

code for SecondaryForm

Spoiler

namespace SimpleTwoFormsDemo
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;

    public partial class SecondaryForm : Form
    {
        #region Constructors

        public SecondaryForm()
        {
            InitializeComponent();
        }

        #endregion Constructors

        #region Events

        public event EventHandler CustomEventOne;

        public event EventHandler CustomEventTwo;

        #endregion Events

        #region Methods

        public void RaiseCustomEventOne(EventArgs e)
        {
            EventHandler handler = CustomEventOne;
            if (handler != null) handler(this, e);
        }

        public void RaiseCustomEventTwo(EventArgs e)
        {
            EventHandler handler = CustomEventTwo;
            if (handler != null) handler(this, e);
        }

        private void btnClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void btnCustomEventOne_Click(object sender, EventArgs e)
        {
            RaiseCustomEventOne(EventArgs.Empty);
        }

        private void btnCustomEventTwo_Click(object sender, EventArgs e)
        {
            RaiseCustomEventTwo(EventArgs.Empty);
        }

        #endregion Methods
    }
}

[webwired]

tlhIn`toq, on 03 January 2012 - 12:12 PM, said:

Give me a few minutes to assemble a small demo project to attach for you

Thank you very much for your extended help, I most certainly appreciate your time and patience. Your code example couldn't have been easier to follow and worked perfectly. I definitely learned something and this'll go in my code snippet bank, literally and figuratively.

[RexGrammer]

Can you subscribe to the first form's close event in the second ones designer code?