i am working on compact framework 3.5, with this issue.ScanOutMenu is a form with two buttons and only in this screen BringToFront() is not working.In all other screen i have input field where it got focus and BringToFront() take the form in front.
private void menuItem1_Click(object sender, EventArgs e)
{
this.Close();
ScanOutMenu scanOutMenu = new ScanOutMenu();
scanOutMenu.BringToFront();
}
Also I tried scanOutMenu.TopMost = true; which is also not working.I think since ScanOutMenu form don't have input field and no focus BringToFront() is not working.
ScanOutMenu form is the main application form and i need to bring the screen in front without using scanOutMenu.Show() or scanOutMenu.ShowDialog()
Have you tried Enabling the TopMost Property?
this.TopMost = true;
//then if you want to remove it just put to false
Sooner or later, when working on a CE app, you have to get your hands dirty with Windows API calls. SetForegroundWindow may do what you're after
// Import the API call
[DllImport("coredll.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd);
// Then, in your code somewhere
SetForegroundWindow(scanOutMenu.Handle);
See API docs here: http://msdn.microsoft.com/en-us/library/ms940024.aspx
If you already have it open then you need to bring to front the Object that is open.
In the example you show you are bringing to front a object that has not been shown yet.
ScanOutMenu scanOutMenu = new ScanOutMenu(); // Creates a new object
scanOutMenu.BringToFront(); //Brings to front the Object that is not shown.
So to open it you have to make a non-local variable with the Form you want and assign that variable the Form you want to open.
Example:
class test{
AnotherForm op;
public test(){
AnotherForm nForm = new AnotherForm(); //Starts a form object
op = nForm; // Assigns the form to be shown to the non-local variable
nForm.Show(); // shows the form object to user
}
private void menuItem1_Click(object sender, EventArgs e)
{
op.BringToFront(); //This will work
}
}
I have been stuck with this for some time now. I can't open a new form on button click.
If i create and .Show() form in the start form constructor i will work. I dont get it! :-(
StartUp Form
public Form1()
{
InitializeComponent();
startmessage();
br = Logic.loadXML("theshiiiiiittt.xml");
br2 = br.Clone();
loadboxes();
//serializeTest();
t = new Thread(contactDBUpdate);
//t.IsBackground = true;
t.Start();
}
Button event:
private void resultButton_Click(object sender, EventArgs e)
{
ResultForm rf = new ResultForm(this);
rf.Show();
this.Enabled = false;
}
Hope this is enough.
In my case it was caused by the fact that i wanted to make my forms non-modal. So i changed them from form.ShowDialog(parentForm) to form.Show().
But that caused the ObjectDisposedException if i try to show a form a second time because somewhere in the code was this.Close();. Form.Close also disposes it.
MSDN:
When a form is closed, all resources created within the object are
closed and the form is disposed.
I just needed to change
this.Close();
to
this.Hide();
Found my code problem.
I took one more look at the Stack trace and found i a message "Icon".
this.Icon.Dispose();
Startupform had this line.
This code fixed my problem:
private void resultButton_Click(object sender, EventArgs e)
{
ResultForm rf = new ResultForm(this);
rf.Icon = this.Icon;
rf.Show();
this.Enabled = false;
}
Thanks for the helping hands...
The problem is that your form object loose the scope and is disposed off.
If you want to keep the dialog open, use Form.ShowDialog();
Try this:
private void resultButton_Click(object sender, EventArgs e)
{
using(ResultForm rf = new ResultForm(this))
{
rf.ShowDialog();
}
this.Enabled = false;
}
Wile Implementing singleton pattern on windows form I got this error too.
The solution is that you have to assign a null value to the static reference in
protected override void Dispose(bool disposing)
by putting simple line.
obj=null; //obj is the static reference in the class.
I'm working in C# with WinForms in a large application with multiple forms.
At several points I have another form coming up as a progress screen. Because I can't freeze my UI thread, I have to start the new form in a new thread. I'm using progressform.ShowDialog() to start the form, but because it's in a new thread, it is possible to Click or Alt + Tab back to the main form. I want to disable this.
My thought is that I can put an EventHandler on the mainForm.GotFocus event and redirect focus to progressForm if it is shown. However, the GotFocus event isn't being triggered when you switch applications or move between the progressForm and mainForm. I'm guessing that it's because some element in mainForm has focus, not the form itself.
If anyone knows of a better way to do this (I'm not committed to the EventHandler approach) or working code for the EventHandler approach, it would solve my problem.
Edit
As per the comment, I tried using the Activated event.
// in InitializeForm()
this.Activated += FocusHandler;
// outside of InitializeForm()
void FocusHandler(object sender, EventArgs e)
{
if (ProgressForm != null)
{
ProgressForm.Focus();
}
}
But it still allowed me to click back to the main form and click buttons.
I've tried some ways and found this which does work as you want, the whole idea is to filter some message from your main UI when your progress form is shown:
public partial class Form1 : Form
{
[DllImport("user32")]
private static extern int SetForegroundWindow(IntPtr hwnd);
public Form1()
{
InitializeComponent();
}
ChildUI child = new ChildUI();
bool progressShown;
IntPtr childHandle;
//I suppose clicking on the button1 on the main ui form will show a progress form.
private void button1_Click(object sender, EventArgs e)
{
if(!progressShown)
new Thread(() => { progressShown = true; childHandle = child.Handle; child.ShowDialog(); progressShown = false; }).Start();
}
protected override void WndProc(ref Message m)
{
if (progressShown&&(m.Msg == 0x84||m.Msg == 0xA1||m.Msg == 0xA4||m.Msg == 0xA3||m.Msg == 0x6))
//0x84: WM_NCHITTEST
//0xA1: WM_NCLBUTTONDOWN
//0xA4: WM_NCRBUTTONDOWN
//0xA3 WM_NCLBUTTONDBLCLK //suppress maximizing ...
//0x6: WM_ACTIVATE //suppress focusing by tab...
{
SetForegroundWindow(childHandle);//Bring your progress form to the front
return;//filter out the messages
}
base.WndProc(ref m);
}
}
if you want to show your progress form normally (not a Dialog), using Application.Run(), showing form normally (using Show()) without processing some while loop will terminate the form almost right after showing it:
private void button1_Click(object sender, EventArgs e)
{
//progressShown = true;
//child.Show();
if (!progressShown)
{
new Thread(() => {
progressShown = true;
if (child == null) child = new ChildUI();
childHandle = child.Handle;
Application.Run(child);
child = null;
progressShown = false;
}).Start();
}
}
I've tested and it works like a charm.
I have the following code in C#:
Form f = new MyForm();
f.Visible = false;
f.Show();
f.Close();
Despite the f.Visible = false, I am seeing a flash of the form appearing and then disappearing. What do I need to do to make this form invisible?
I need to show the form (invisibly) during the splash of my app because doing this removes a cold start delay when showing this form.
If you want to show the form without actually seeing it, you can do this:
public Form1()
{
InitializeComponent();
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.ShowInTaskbar = false;
this.Load += new EventHandler(Form1_Load);
}
void Form1_Load(object sender, EventArgs e)
{
this.Size = new Size(0, 0);
}
If at a later point you want to show it, you can just change everything back. Here is an example after 10 seconds, it shows the form:
Timer tmr = new Timer();
public Form1()
{
tmr.Interval = 10000;
tmr.Tick += new EventHandler(tmr_Tick);
tmr.Start();
InitializeComponent();
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.ShowInTaskbar = false;
this.Load += new EventHandler(Form1_Load);
}
void tmr_Tick(object sender, EventArgs e)
{
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Sizable;
this.ShowInTaskbar = true;
this.Size = new Size(300, 300);
}
void Form1_Load(object sender, EventArgs e)
{
this.Size = new Size(0, 0);
}
By far the simplest way to keep a form invisible is just by not showing it. It is a big deal in Winforms, calling Show() or setting the Visible property to true (same thing) does a lot of things. It is the way the native Windows window gets created. In typical .NET 'lazy' fashion. Any attempt to set Visible back to false (like in OnLoad) will be defeated.
Technically it is possible, you have to override the SetVisibleCore() method. Like this:
protected override void SetVisibleCore(bool value) {
if (!this.IsHandleCreated) {
this.CreateHandle();
value = false; // Prevent window from becoming visible
}
base.SetVisibleCore(value);
}
This ensures that the window doesn't become visible the first time you call Show(). Which is handy when you have NotifyIcon for example, you typically want the icon directly in the notification area and only display a window when the user clicks on the icon. Beware that OnLoad() doesn't run until the window actually becomes visible so move code to the constructor or the override if necessary.
Simply Because f.Show() is making the form Visible again and f.Close() is Closing it... so the flash.
If you see the MSDN doc for Form.Show() method it clearly mentions that:
Showing the control is equivalent to setting the Visible property to true. After the Show method is called, the Visible property returns a value of true until the Hide method is called.
If you don't want the flash just don't show the Form at all.
You need to edit the MyForm class, and add the following override method:
protected override void SetVisibleCore(bool value)
{
//just override here, make sure that the form will never become visible
if (!IsHandleCreated) CreateHandle();
value = false;
base.SetVisibleCore(value);
}
You should ask yourself if this is really necessary however - probably indicative of poor design really.
Edit:
It's pretty rare that you need to do this, the only situation I've used it is when I needed a form I could place a COM component on (since the COM component needed a Window handle), and I had to run Application.Run(formInstance) which calls the Show method of the form. By forcing the form to always be invisible, you get a window handle and a message loop without seeing anything on screen.
I've created helper method that will to show invisible form and subsequent Show calls will show window as usually:
public static class FormHelper
{
public static void ShowInvisible(this Form form)
{
// saving original settings
bool needToShowInTaskbar = form.ShowInTaskbar;
WindowState initialWindowState = form.WindowState;
// making form invisible
form.ShowInTaskbar = false;
form.WindowState = FormWindowState.Minimized;
// showing and hiding form
form.Show();
form.Hide();
// restoring original settings
form.ShowInTaskbar = needToShowInTaskbar;
form.WindowState = initialWindowState;
}
}
So form will be rendered (and Load event will trigger) without any blink.
I have an application with one form in it, and on the Load method I need to hide the form.
The form will display itself when it has a need to (think along the lines of a outlook 2003 style popup), but I can' figure out how to hide the form on load without something messy.
Any suggestions?
I'm coming at this from C#, but should be very similar in vb.net.
In your main program file, in the Main method, you will have something like:
Application.Run(new MainForm());
This creates a new main form and limits the lifetime of the application to the lifetime of the main form.
However, if you remove the parameter to Application.Run(), then the application will be started with no form shown and you will be free to show and hide forms as much as you like.
Rather than hiding the form in the Load method, initialize the form before calling Application.Run(). I'm assuming the form will have a NotifyIcon on it to display an icon in the task bar - this can be displayed even if the form itself is not yet visible. Calling Form.Show() or Form.Hide() from handlers of NotifyIcon events will show and hide the form respectively.
Usually you would only be doing this when you are using a tray icon or some other method to display the form later, but it will work nicely even if you never display your main form.
Create a bool in your Form class that is defaulted to false:
private bool allowshowdisplay = false;
Then override the SetVisibleCore method
protected override void SetVisibleCore(bool value)
{
base.SetVisibleCore(allowshowdisplay ? value : allowshowdisplay);
}
Because Application.Run() sets the forms .Visible = true after it loads the form this will intercept that and set it to false. In the above case, it will always set it to false until you enable it by setting allowshowdisplay to true.
Now that will keep the form from displaying on startup, now you need to re-enable the SetVisibleCore to function properly by setting the allowshowdisplay = true. You will want to do this on whatever user interface function that displays the form. In my example it is the left click event in my notiyicon object:
private void notifyIcon1_MouseClick(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
this.allowshowdisplay = true;
this.Visible = !this.Visible;
}
}
I use this:
private void MainForm_Load(object sender, EventArgs e)
{
if (Settings.Instance.HideAtStartup)
{
BeginInvoke(new MethodInvoker(delegate
{
Hide();
}));
}
}
Obviously you have to change the if condition with yours.
protected override void OnLoad(EventArgs e)
{
Visible = false; // Hide form window.
ShowInTaskbar = false; // Remove from taskbar.
Opacity = 0;
base.OnLoad(e);
}
At form construction time (Designer, program Main, or Form constructor, depending on your goals),
this.WindowState = FormWindowState.Minimized;
this.ShowInTaskbar = false;
When you need to show the form, presumably on event from your NotifyIcon, reverse as necessary,
if (!this.ShowInTaskbar)
this.ShowInTaskbar = true;
if (this.WindowState == FormWindowState.Minimized)
this.WindowState = FormWindowState.Normal;
Successive show/hide events can more simply use the Form's Visible property or Show/Hide methods.
Try to hide the app from the task bar as well.
To do that please use this code.
protected override void OnLoad(EventArgs e)
{
Visible = false; // Hide form window.
ShowInTaskbar = false; // Remove from taskbar.
Opacity = 0;
base.OnLoad(e);
}
Thanks.
Ruhul
Extend your main form with this one:
using System.Windows.Forms;
namespace HideWindows
{
public class HideForm : Form
{
public HideForm()
{
Opacity = 0;
ShowInTaskbar = false;
}
public new void Show()
{
Opacity = 100;
ShowInTaskbar = true;
Show(this);
}
}
}
For example:
namespace HideWindows
{
public partial class Form1 : HideForm
{
public Form1()
{
InitializeComponent();
}
}
}
More info in this article (spanish):
http://codelogik.net/2008/12/30/primer-form-oculto/
I have struggled with this issue a lot and the solution is much simpler than i though.
I first tried all the suggestions here but then i was not satisfied with the result and investigated it a little more.
I found that if I add the:
this.visible=false;
/* to the InitializeComponent() code just before the */
this.Load += new System.EventHandler(this.DebugOnOff_Load);
It is working just fine.
but I wanted a more simple solution and it turn out that if you add the:
this.visible=false;
/* to the start of the load event, you get a
simple perfect working solution :) */
private void
DebugOnOff_Load(object sender, EventArgs e)
{
this.Visible = false;
}
You're going to want to set the window state to minimized, and show in taskbar to false. Then at the end of your forms Load set window state to maximized and show in taskbar to true
public frmMain()
{
Program.MainForm = this;
InitializeComponent();
this.WindowState = FormWindowState.Minimized;
this.ShowInTaskbar = false;
}
private void frmMain_Load(object sender, EventArgs e)
{
//Do heavy things here
//At the end do this
this.WindowState = FormWindowState.Maximized;
this.ShowInTaskbar = true;
}
Put this in your Program.cs:
FormName FormName = new FormName ();
FormName.ShowInTaskbar = false;
FormName.Opacity = 0;
FormName.Show();
FormName.Hide();
Use this when you want to display the form:
var principalForm = Application.OpenForms.OfType<FormName>().Single();
principalForm.ShowInTaskbar = true;
principalForm.Opacity = 100;
principalForm.Show();
This works perfectly for me:
[STAThread]
static void Main()
{
try
{
frmBase frm = new frmBase();
Application.Run();
}
When I launch the project, everything was hidden including in the taskbar unless I need to show it..
Override OnVisibleChanged in Form
protected override void OnVisibleChanged(EventArgs e)
{
this.Visible = false;
base.OnVisibleChanged(e);
}
You can add trigger if you may need to show it at some point
public partial class MainForm : Form
{
public bool hideForm = true;
...
public MainForm (bool hideForm)
{
this.hideForm = hideForm;
InitializeComponent();
}
...
protected override void OnVisibleChanged(EventArgs e)
{
if (this.hideForm)
this.Visible = false;
base.OnVisibleChanged(e);
}
...
}
Launching an app without a form means you're going to have to manage the application startup/shutdown yourself.
Starting the form off invisible is a better option.
This example supports total invisibility as well as only NotifyIcon in the System tray and no clicks and much more.
More here: http://code.msdn.microsoft.com/TheNotifyIconExample
As a complement to Groky's response (which is actually the best response by far in my perspective) we could also mention the ApplicationContext class, which allows also (as it's shown in the article's sample) the ability to open two (or even more) Forms on application startup, and control the application lifetime with all of them.
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
MainUIForm mainUiForm = new MainUIForm();
mainUiForm.Visible = false;
Application.Run();
}
I had an issue similar to the poster's where the code to hide the form in the form_Load event was firing before the form was completely done loading, making the Hide() method fail (not crashing, just wasn't working as expected).
The other answers are great and work but I've found that in general, the form_Load event often has such issues and what you want to put in there can easily go in the constructor or the form_Shown event.
Anyways, when I moved that same code that checks some things then hides the form when its not needed (a login form when single sign on fails), its worked as expected.
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Form1 form1 = new Form1();
form1.Visible = false;
Application.Run();
}
private void ExitToolStripMenuItem_Click(object sender, EventArgs e)
{
this.Close();
Application.Exit();
}
Here is a simple approach:
It's in C# (I don't have VB compiler at the moment)
public Form1()
{
InitializeComponent();
Hide(); // Also Visible = false can be used
}
private void Form1_Load(object sender, EventArgs e)
{
Thread.Sleep(10000);
Show(); // Or visible = true;
}
In the designer, set the form's Visible property to false. Then avoid calling Show() until you need it.
A better paradigm is to not create an instance of the form until you need it.
Based on various suggestions, all I had to do was this:
To hide the form:
Me.Opacity = 0
Me.ShowInTaskbar = false
To show the form:
Me.Opacity = 100
Me.ShowInTaskbar = true
Why do it like that at all?
Why not just start like a console app and show the form when necessary? There's nothing but a few references separating a console app from a forms app.
No need in being greedy and taking the memory needed for the form when you may not even need it.
I do it like this - from my point of view the easiest way:
set the form's 'StartPosition' to 'Manual', and add this to the form's designer:
Private Sub InitializeComponent()
.
.
.
Me.Location=New Point(-2000,-2000)
.
.
.
End Sub
Make sure that the location is set to something beyond or below the screen's dimensions. Later, when you want to show the form, set the Location to something within the screen's dimensions.