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Enable/Disable Buttons On Owner Form When Owned Form Is Closed

I am working on a WinForms Desktop application in C# .NET. The target framework is .NET Framework 4.8. When the application is started, the main form is displayed with several buttons. Each button hides the main form when clicked and opens another form that displays data with which the user interacts. The main form is the owner of the new form.One button opens a form that presents a list of files from a network share folder in a data grid view. The user selects a row in the data grid and clicks a button to import the information in the file to various tables in a SQL Server database. When the import is complete, the selected row is removed from the data grid. When the user closes this form, there is code in the Form Closed event to show the owner. This all works well.My problem is that when the main form is unhidden, I need to disable the button that opens the form to list files to import if there are not any files in the network share folder to be imported. There is also a line of code to change the button's text property informing the user there are not any files to import.I realize I can place the code to disable the button and change button text in the VisibleChanged event. But, I only want the code to run after the owned form's closed event shows the owner form. How do I enclose the code in the main form's VisibleChanged event to disable the file import button only after the owned form is closed. Or, is it possible to edit the properties of the button on the owner form in the Form Closed event prior to the Owner.Show();I found a similar question WinForm Form Closed Event. But when I follow the suggestion
private void LoadChildForm_Click(object sender, EventArgs e)
{
ChildForm form = new ChildForm();
form.FormClosed += new FormClosedEventHandler(ChildFormClosed);
form.Show();
}
substituting my names
private void btnImportHFR_Click(object sender, EventArgs e)
{
Form form = new frmHFRFiles();
form.FormClosed += new FormClosedEventHandler(frmHFRFiles_FormClosed);
form.Show(this);
Hide();
}
Visual Studio flags frmHFRFiles_FormClosed as an error for the name does not exist in the current context.

ChildForm form = new ChildForm(this);
Then in ChildForm constructor:
MainForm m_MainForm;
Public ChildForm (MainForm mainForm)
{
m_MainForm = mainForm;
}
Then in closing event:
m_MainForm.button1.Enabled = false;
Ensure button1 is public

Here is what I did. I created a boolean variable in the main form and set the initial value to false.
private bool updateButtons = false;
The main form's constructor executes the search for files in the network folder.
public frmMainMenu()
{
InitializeComponent();
Shared.FilesForImport = GetHFRFiles();
}
The form's load event calls the EnableButtons() method
public void EnableButtons()
{
btnImportHFR.Enabled = Convert.ToBoolean(Shared.FilesForImport.Count);
btnImportHFR.Text = btnImportHFR.Enabled ? "Find Available HFR" : "No HFR For Import";
btnGetFacilityStatus.Enabled = Shared.sqlWrap.GetDataForFacStat(Shared.DsFacStat);
updateButtons = false;
}
The main form's visible changed event fires after the form load event. The network folder is not searched again because the updateButtons value is set to false.
private void frmMainMenu_VisibleChanged(object sender, EventArgs e)
{
if(updateButtons)
{
EnableButtons();
}
}
In the button click event, the updateButtons value is set to true after the main form is hidden.
private void btnImportHFR_Click(object sender, EventArgs e)
{
frmHFRFiles form = new frmHFRFiles();
form.Show(this);
Hide();
updateButtons = true;
}
The child form's closed event calls the Owner.Show() method
private void frmHFRFiles_FormClosed(object sender, FormClosedEventArgs e)
{
Owner.Show();
}
This causes the main form's visible changed event to fire. Only this time the EnableButtons() method will run because the updateButtons value is true.
private void frmMainMenu_VisibleChanged(object sender, EventArgs e)
{
if(updateButtons)
{
EnableButtons();
}
}
public void EnableButtons()
{
btnImportHFR.Enabled = Convert.ToBoolean(Shared.FilesForImport.Count);
btnImportHFR.Text = btnImportHFR.Enabled ? "Find Available HFR" : "No HFR For Import";
btnGetFacilityStatus.Enabled = Shared.sqlWrap.GetDataForFacStat(Shared.DsFacStat);
updateButtons = false;
}
Finally, the EnableButtons() method sets the updateButtons value to false.
It seems rudimentary to me, but it works. Thank you everyone for your feedback.

My problem is that when the main form is unhidden, I need to disable the button that opens the form to list files to import if there are not any files in the network share folder to be imported. There is also a line of code to change the button's text property informing the user there are not any files to import.
So your main form has a button X. If this button is clicked a method is called. This method will first hide the form, then show the subform until the subform is closed. The method should disable button X, change the button's text and unhide the form.
To make this flexible, we won't do everything in one procedure, we make several procedures with the intention of the procedure: "Inform operator there are no files to import" "Disable opening the subform", and of course their counterparts "Enable opening the subform", "Inform operator there are files to import"
TODO: invent proper method names
private void ShowNoFilesToImport()
{
this.buttonX.Text = ...;
}
private void DisableOpeningSubForm()
{
this.buttonX.Text.Enabled = false;
}
The advantage of this, is that if you later want to change the way that you want to inform the operator, for instance if you want to use an information field at the bottom of you screen, you will only have to change this in one place.
Furthermore, you can reuse the procedures, for instance you can add a menu item that will do the same as button X, this menu item can call the same methods
private void PerformActionsButtonX() // TODO: invent proper name
{
// Hide this form, and show the Subform until it is closed
this.Visible = false;
using (var dlg = new SubForm())
{
// if needed, set properties of the subForm:
dlg.Text = ...
dlg.Position = ...
// show the form until it is closed
var dlgResult = dlg.ShowDialog();
this.ProcessDlgResult(dlgResult, dlg);
}
// Show that there are no files to Import and disable OpeningSubform
this.ShowNoFilesToImport();
this.DisableOpeningSubform();
// Finally: show this form:
this.Visible = true;
}
And of course call this method when ButtonX or menu item Y are clicked:
private void OnButtonX_Clicked(object sender, ...)
{
this.PerformActionsButtonX();
}
private void OnMenyItemYClicked(object sender, ...)
{
this.PerformActionsButtonX();
}

Switching between Window Forms does not seem to work

Hey there StackOverflow community!
So I've been working on an application that checks if the user has entered valid credentials in a Login() form, then it switches over to an Intro_Sequence() form (where a .mp4 file is played in fullscreen mode) as a sort of aesthetic addition to the app. So far so good, no problems whatsoever.
The problem comes right after the Intro ends, where supposedly the application should switch over to a third form, called Main().
I have implemented a check whenever Windows Media Player (aka axWMPLib) changes its PlayState to see whether it has finished the playback.
If it has, then the Hide() event is called to conceal the current Form's window, then main.ShowDialog() should open the third form.
Afterwards, I call the Close() event to close the previous Form's window entirely.
Here is the code so far:
public partial class Intro_Sequence : Form
{
public static string Username;
public Intro_Sequence(string username)
{
InitializeComponent();
Username = username;
FormBorderStyle = FormBorderStyle.None;
Bounds = Screen.PrimaryScreen.Bounds;
TopMost = true;
intro.uiMode = "none";
intro.URL = AppDomain.CurrentDomain.BaseDirectory + "\\Intro.mp4";
intro.enableContextMenu = false;
DisableMouseClicks();
}
private void DisableMouseClicks()
{
if (this.Filter == null)
{
this.Filter = new MouseClickMessageFilter();
Application.AddMessageFilter(this.Filter);
}
}
private MouseClickMessageFilter Filter;
private const int LButtonDown = 0x201;
private const int LButtonUp = 0x202;
private const int LButtonDoubleClick = 0x203;
public class MouseClickMessageFilter : IMessageFilter
{
public bool PreFilterMessage(ref System.Windows.Forms.Message m)
{
switch (m.Msg)
{
case LButtonDown:
case LButtonUp:
case LButtonDoubleClick:
return true;
}
return false;
}
}
private void Intro_Sequence_Load(object sender, EventArgs e)
{
}
private void intro_PlayStateChange(object sender, AxWMPLib._WMPOCXEvents_PlayStateChangeEvent e)
{
if(intro.playState == WMPLib.WMPPlayState.wmppsMediaEnded)
{
Main main = new Main(Username);
this.Hide();
main.ShowDialog();
this.Close();
}
}
}
As you can see I have also added a filter to block clicks during playback, so as not to allow the user to pause it.
However, when I execute this code, it works perfectly fine until it finishes the video and then closes abruptly.
I tried putting breakpoints and everything seems to be fine.
It does call everything I tell it to call, yet the form doesn't even appear.
I have also tried several other alternatives, like not closing the Form at all, calling Show() instead of ShowDialog() and even not Hiding it at all.
It is as if it either freezes there or closes instantly without any sign of the Main form showing.
I also tried calling the Main() form from the Login() and it works perfectly from there.
I really don't know what is going on.
Any help would be appreciated.

How about something like this?
There are three forms. There's a Login form (in this case, it's just an empty form - you close it by clicking on the red X). It is popped up modally from within the Main form (while the main form is hidden).
There's a Splash screen on which your video is to play. I fake out the video by using await Task.Delay(4000); to get a pause. After the 4 second delay, I raise an event (equivalent to your media player event). What I do is show this modally from the main form. I put the event handler in this form; when the event is raised, I close the splash screen modal. The entire (non-designer) code for that form looks like (and, since there are no controls on this form, the designer code is pretty lean):
public partial class SplashScreen : Form
{
public event EventHandler SplashFinished;
public SplashScreen()
{
InitializeComponent();
this.SplashFinished += SplashScreen_SplashFinished;
}
private async void SplashScreen_Load(object sender, EventArgs e)
{
await Task.Delay(4000);
SplashFinished?.Invoke(this, new EventArgs());
}
private void SplashScreen_SplashFinished(object sender, EventArgs e)
{
this.DialogResult = DialogResult.OK;
this.Close();
}
}
Then there's the Main form. It gets fired up in the normal way from Program.cs:
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
The only thing that I added to that form (from the out-of-the-box code) is:
private void Form1_Load(object sender, EventArgs e)
{
this.Hide();
var login = new LoginForm();
//should really check this, but for now
login.ShowDialog(this);
var splash = new SplashScreen();
splash.ShowDialog(this);
this.Show();
}
So, when the app starts, the user is shown the login form (the main form is hidden). He does what is needed to do (and the result is checked in the main form's Form1_Load handler.
If everything is cool, a new SplashScreen form is created and shown modally. When it pops up, the video starts (in this case, the video is simply an asynchronous timer). When the video ends, the SplashScreen handles the finished event, and uses it to close itself.
Once control returns to the main form, it displays itself.

c# override CreateParams and WndProc without form [duplicate]

I've successfully created an app that minimizes to the tray using a NotifyIcon. When the form is manually closed it is successfully hidden from the desktop, taskbar, and alt-tab. The problem occurs when trying to start with the app minimized. At first the problem was that the app would be minimized but would still appear in the alt-tab dialog. Changing the FormBorderStyle to one of the ToolWindow options (from the "None" option) fixed this, but introduced another problem. When the app first starts the titlebar of the minimized window is visible just above the start menu:
Opening the form and the closing it causes it to hide properly. I've tried lots of variations, but here's essentially how it's working right now...
WindowState is set to Minimized in the Designer. After some initialization in the constructor I have the following lines:
this.Visible = false;
this.ShowInTaskbar = false;
When the NotifyIcon is double-clicked I have the following:
this.WindowState = FormWindowState.Normal;
this.Visible = true;
this.ShowInTaskbar = true;
Like I said, I've tried lots of minor variations on this (this.Hide(), etc.). Is there a way to have the NotifyIcon be the primary component such that I can completely start and dispose of the form while leaving the NotifyIcon running? There's got to be a way to start the app with the form minimized without any of the weirdness. Please help me find it!

The right way to do this is to prevent the form from getting visible in the first place. That requires overriding SetVisibleCore(). Let's assume a context menu for the NotifyIcon with a Show and Exit command. You can implement it like this:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
notifyIcon1.ContextMenuStrip = contextMenuStrip1;
this.showToolStripMenuItem.Click += showToolStripMenuItem_Click;
this.exitToolStripMenuItem.Click += exitToolStripMenuItem_Click;
}
private bool allowVisible; // ContextMenu's Show command used
private bool allowClose; // ContextMenu's Exit command used
protected override void SetVisibleCore(bool value) {
if (!allowVisible) {
value = false;
if (!this.IsHandleCreated) CreateHandle();
}
base.SetVisibleCore(value);
}
protected override void OnFormClosing(FormClosingEventArgs e) {
if (!allowClose) {
this.Hide();
e.Cancel = true;
}
base.OnFormClosing(e);
}
private void showToolStripMenuItem_Click(object sender, EventArgs e) {
allowVisible = true;
Show();
}
private void exitToolStripMenuItem_Click(object sender, EventArgs e) {
allowClose = true;
Application.Exit();
}
}
Note a wrinkle with the Load event, it won't fire until the main form is first shown. So be sure to do initialization in the form's constructor, not the Load event handler.

I'm reading all the answers and see hacks and black magic... (no offense, mates)
No hacks needed. You don't even have to set "ShowInTaskbar=false" and other stuff. Just do this:
//"Form Shown" event handler
private void Form_Shown(object sender, EventArgs e)
{
//to minimize window
this.WindowState = FormWindowState.Minimized;
//to hide from taskbar
this.Hide();
}
NOTE: I strongly recommend NOT TOUCHING the "ShowInTaskbar" property. For example, if your application registers system-wide hotkeys or other similar stuff (hooks, etc) - setting ShowInTaskBar=false and minimizing your app will prevent Windows from sending some messages to your window... And your hooks/hotkeys/etc will stop working.

In the constructor, remove these two lines:
this.Visible = false;
this.ShowInTaskbar = false;
and add after InitializeComponent();:
this.WindowState = FormWindowState.Minimized;
In designer, set ShowInTaskbar to false & FormWindowState to Normal.
EDIT:
If you post the same in Load event, the window does get minimized but still shows minimized on the desktop. I think this is a bug.

When minimizing an application and you want to hide it from Alt+Tab:
You also need to set the Opacity to stop the titlebar showing near the Start Menu when you set the Border Style to a Tool Window.
On Minimize Event:
this.Visible = false;
this.Opacity = 0;
this.FormBorderStyle = FormBorderStyle.FixedToolWindow;
this.ShowInTaskbar = false;
On Normalize Event:
this.Visible = true;
this.Opacity = 100;
this.FormBorderStyle = FormBorderStyle.FixedSingle; //or whatever it was previously set to
this.ShowInTaskbar = true;

Move the following code from the Form's constructor to Form_Main_Load(). With the same setup on Notification_Icon when Form_Resize().
// Hide the Form to System Tray
this.WindowState = FormWindowState.Minimized;

This "quick and dirty fix" worked for me:
$form1.FormBorderStyle = "fixedtoolwindow"
$form1.top = -1000000
$form1.Left = -1000000
$form1.Width = 10
$form1.Height = 10
$form1.WindowState = "normal"
$form1.ShowInTaskbar = $False
$form1.Opacity = 0
$form1.Hide()
Hope it helps someone else...

Why Won't Form Get Focus?

I have a form that is launched modally like this:
private void find_street_Click(object sender, EventArgs e)
{
this.WindowState = FormWindowState.Minimized;
Form findForm = new FindStreet();
findForm.ShowDialog();
this.WindowState = FormWindowState.Normal;
}
The form launches correctly, and the cursor is in the first text box, whose TabIndex is set to 1.
Along with the InitializeComponent(); call, these commands are present.
public FindStreet()
{
InitializeComponent();
this.TopMost = true;
this.BringToFront();
this.Focus();
}
I have looked at and tried a number of examples. The cursor appears in the correct control, but the form's window does not have the focus. The problem is that if a user starts typing, even though the newly launched form is visible, those keystrokes are not going into the text box.

Remove the code in public FindStreet() and in load event of FindStreet add:
this.TopMost = true; //i don't know why you need this.
this.Activate();
When you minimize your main form the next one in z-order get the cursor. this.Focus() doesn't do anything. You need to Activate the dialog.

A dialog requires an owner, that cannot be a minimized window. Now accidents start to happen, starting with your WindowState assignment. Your app doesn't have a window left that can receive the focus so Windows is forced to find another one, that will be one owned by another application. Same problem happens when you close the dialog.
You can still get the intended effect, you must hide your main window after the dialog is displayed, show it again before the dialog closes. That requires a bit of hackorama:
using (var dlg = FindStreet()) {
// Show main window when dialog is closing
dlg.FormClosing += new FormClosingEventHandler((s, cea) => {
if (!cea.Cancel) this.Show();
});
// Hide main window after dialog is shown
this.BeginInvoke(new Action(() => {
this.Hide();
}));
dlg.StartPosition = FormStartPosition.Manual;
dlg.Location = this.Location;
if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK) {
// etc...
}
}
And remove the hacks from the FindStreet constructor. Watch out for event order if you have a FormClosing event handler in FindStreet, be sure to override OnFormClosing() instead.

If you want to set a specific control as the current active control then try this:
this.ActiveControl = myTextBox;
This will place the cursor you want as the main focus, when the form loads. So try this out:
public FindStreet()
{
InitializeComponent();
this.TopMost = true;
this.BringToFront();
this.Focus();
this.ActiveControl = myTextBox;
}
Here is the link to Focus() which should explain why your focus call was not working.

C#.NET MDI bugs when programmatically hiding and showing again a maximized child form and when maximized, child form's icon cannot be changed

Basically I am having two problems with C#.NET MDI. You can download VS2010 solution which reproduces bugs here.
1) When programmatically hiding and showing again a maximized child form, it is not maximized properly again and becomes neither maximized or in normal state.
childForm = new Form();
childForm.Text = "Child Form";
childForm.MdiParent = this;
...
private void showButton_Click(object sender, EventArgs e)
{
childForm.Visible = true;
}
...
private void hideButton_Click(object sender, EventArgs e)
{
childForm.Visible = false;
}
When child form is maximized, then programicaly hidden and shown again, it becomes something like this (please notice the menu bar - child form's control box appears, but child form is not maximized):
At this stage, child form cannot be moved around. However, I found a workaround for that, simply by showing and hiding a dummy child form, which forces the actual child form to become properly maximized. But this makes MDI area to flicker. Tried Invalidate, Refresh, Update methods, but they don't help. Maybe there are other workarounds to overcome this bug and not to make MDI area flicker with dummy child form?
private void workaround1Button_Click(object sender, EventArgs e)
{
dummyForm.Visible = true;
dummyForm.Visible = false;
}
2) When child form is maximized, the icon of the child form is displayed on menu bar. However, if you have to change the icon while the child form is maximized, the icon on the menu bar is not being refreshed (see the image above). I found a workaround for that too, which basically hides and shows menu bar. Icon gets refreshed, but it makes everything below menu bar to flicker. Tried Invalidate, Refresh, Update methods, but they don't help. Is there any other way to make menu bar to refresh the child form's icon?
private void workaround2Button_Click(object sender, EventArgs e)
{
menuStrip.Visible = false;
menuStrip.Visible = true;
}
Also I noticed that when parent form is in normal window state mode (not maximized) and you change the width or height of the form by 1 pixel, child form becomes maximized as it should be and child form's icon on menu bar gets refreshed properly and you don't need other workaround I described above. If I change the size of the form programicaly, form flickers by 1 pixel and I cannot do that, when parent form is maximized. Is there any way how I could invoke the repaint/refresh functionality which is called when you resize a form and which makes child form become maximized properly and the icon on the menu bar refreshed?

There's a bug in the implementation of the internal MdiControlStrip class, the control that displays the icon and the min/max/restore glyphs in the parent window. I haven't characterized it as yet, the code isn't that easy. A classic side effect of the bug is that the glyphs get doubled up, you found some other side-effects. The fix is simple though, delay creating the child windows until after the constructor is completed. Like this:
public MainForm()
{
InitializeComponent();
}
protected override void OnLoad(EventArgs e) {
childForm = new Form();
childForm.Text = "Child Form";
childForm.MdiParent = this;
dummyForm = new Form();
dummyForm.MdiParent = this;
dummyForm.WindowState = FormWindowState.Maximized;
base.OnLoad(e);
}

Have you tired using Hide/Show instead of setting visible to true/false?
Try:
private void showButton_Click(object sender, EventArgs e)
{
childForm.Show();
}
private void hideButton_Click(object sender, EventArgs e)
{
childForm.Hide();
}

How about this workaround?
private void showButton_Click(object sender, EventArgs e)
{
childForm.Visible = true;
childForm.WindowState = (FormWindowState)childForm.Tag;
}
private void hideButton_Click(object sender, EventArgs e)
{
childForm.Visible = false;
childForm.Tag = childForm.WindowState;
childForm.WindowState = FormWindowState.Normal;
}
UPDATE
I just gave you the idea how you could do. A better solution using the same idea as above would be a new base form which saves the windows state. See below. Derive your forms from FixedForm instead of Form:
public partial class FixedForm : Form
{
private FormWindowState lastWindowState;
public FixedForm()
{
InitializeComponent();
}
protected override void OnVisibleChanged(EventArgs e)
{
base.OnVisibleChanged(e);
if (Visible)
{
WindowState = lastWindowState;
}
else
{
lastWindowState = WindowState;
WindowState = FormWindowState.Normal;
}
}
}

Found a way how to come around those bugs.
First of all you need to suspend painting for a form and its children. I found a very helpful thread here, which describes how to do it.
After suspending painting, you need call UpdateBounds method of the control and increase ClientRectangle Width or Height by one and then decrease it back to the same value it was before. This invokes layout functionality which makes everything to update/repaint. Last step is to enable painting. Not very nice solution I guess, but it works.
StopDrawing();
UpdateBounds(Location.X, Location.Y, Width, Height, ClientRectangle.Width, ClientRectangle.Height + 1);
UpdateBounds(Location.X, Location.Y, Width, Height, ClientRectangle.Width, ClientRectangle.Height - 1);
StartDrawing();
I find suspending painting very helpful not only for working around those two bugs, but also in general to make GUI work more smoothly. I guess this can help to remove any kind of flickering. However, this solution requires P/Invokes, which should be avoided in general.

Why not just manually reset required icon in menuStrip items, after the creation of the window:
menuStripMain.Items[0].Image = null;