How can i make a form so that it can never be closed by pressing the "X" button ?
Hook the form's Closing event, like this:
myForm.Closing += MyForm_Closing;
public void MyForm_Closing(object sender, FormClosingEventArgs e)
{
e.Cancel = true;
}
Use with caution, deviating from expectation is often a bad idea.
You need to handle the onclosing event
Form1_OnClosing(sender blah, eventarg e)
{
e.Cancel = true;
}
Can't remember the exact syntax 100%
Related
I have a TextChanged event attached to a TextBox in a Windows Form. How to make sure if a particular call to that event wasn't triggered programmatically rather by user interacting with the TextBox?
I would like to extend #rw_'s solution a little. Inside your TextBox event handler,
private void txt_TextChanged(object sender, EventArgs e)
{
if (!(sender is null) &&((TextBox)sender).ContainsFocus)
{
//Code if triggered by Click event
}
else
{
//Code if triggered programmatically
}
}
This will help your program adjust to the case where sender object is not null for some reason.
I am unsure about what your question means. I'll split my answer.
If you want to call the text changed function programmatically and differ when it was called by user interactivity or if it was called programmatically:
Assuming that when you call the function programmatically you pass null on sender and event args txt_TextChanged(null,null);, you could use this solution:
private void txt_TextChanged(object sender, EventArgs e)
{
if(sender == null)
{
// triggered programmatically
}
else
{
// triggered by the user. sender object is the textbox interacted by the user
}
}
If you want to change the text programmatically without triggering the event:
this.txt.TextChanged -= new System.EventHandler(this.txt_TextChanged);
txt.Text = "bar";
this.txt.TextChanged += new System.EventHandler(this.txt_TextChanged);
This is a common problem. You can set a flag on your form before updating the value and then check it in your event handler:
handleEvent = false;
TextBox1.Text = "foo";
handleEvent = true;
Then in your handler, check the flag:
private void TextBox1_TextChanged(object sender, EventArgs e)
{
if(handleEvent)
{
// do stuff
}
}
I use a RepositoryItemSearchLookUpEdit.
I need to prevent SearchLookupEdit from Closing When PopupCloseMode is CloseUpKey.
private void repositoryItemLookUpEdit_CloseUp(object sender, DevExpress.XtraEditors.Controls.CloseUpEventArgs e)
{
if (e.CloseMode == PopupCloseMode.CloseUpKey)
{
//Prevent from Closing
}
}
What should I write Instead of //Prevent from Closing to Achieve this?
As a workaround, you can subscribe to QueryCloseUp event. And check previous pressed key:
private void repositoryItemLookUpEdit_QueryCloseUp(object sender, CancelEventArgs e)
{
e.Cancel = true;
}
I write certain code in my form ResizeEnd event. Now problem is when form is moved by clicking and dragging on the caption bar, ResizeEnd event is fired and code is executed even though form size is NOT changed.
I gone through MSDN documentation for Resizeend event and it says that event will fire when form is moved (don't understand why this happens when the size is NOT changed).
For resolution I put the if condition to check if size is changed like below to stop execution of code on form move:
int Prv_Height; int Prv_Width;
private void TemplateGrid_ResizeEnd(object sender, EventArgs e)
{
if (this.Size.Width != Prv_Width || this.Size.Height != Prv_Height)
{
Prv_Width = this.Size.Width;
Prv_Height = this.Size.Height;
//Other code here when form resize ends...
}
}
So is there any way to stop ResizeEnd event to fire when form is moved? or any other better approach to solve the problem?
You could move your check for sizechange to a new baseform. On derived forms the resizeEnd event will then only fire if the size is actually changed.
public partial class CustomForm : Form
{
private Size _prvSize;
public CustomForm()
{
InitializeComponent();
}
protected override void OnShown(EventArgs e)
{
_prvSize = this.Size;
base.OnShown(e);
}
protected override void OnResizeEnd(EventArgs e)
{
if (this.Size == _prvSize)
return;
_prvSize = this.Size;
base.OnResizeEnd(e);
}
}
private void Form1_ResizeBegin(object sender, EventArgs e)
{
oldSize = ClientSize;
}
private Size oldSize = new Size();
private void Form1_ResizeEnd(object sender, EventArgs e)
{
if (oldSize == ClientSize)
return;
//Add Something
}
I'm having a issue with the following scenario on Windows Forms:
I created a Form with two buttons, each button have been assigned with the behaviour DialogResult OK and DialogResult Cancel, respectively.
But based on certain conditions, I need to stop the execution of the OK button. The problem is that if I just made a return like this:
private void btnOk_Click(object sender, EventArgs e)
{
foreach(Control control in tblTable.Controls)
{
if (control.GetType() == typeof(TextBox))
{
if (control.Text.Trim() == "")
{
control.Focus(); return;
}
}
else
{
}
}
}
The dialog result keeps returning the OK answer to the parent form.
I need to stop the execution of the event and not return any answer until the user corrects the info on the form. In other words, the user should be taken back to the form to correct any missing or wrong data.
As Hans Passant mentions in an comment, just set the DialogResult to None!
Like this:
private void btnOk_Click(object sender, EventArgs e)
{
if(ValidationFailed())
{
this.DialogResult = DialogResult.None;
return;
}
//...
}
Personally I wouldn't use DialogResults on buttons in this scenario. I only tend to set the DialogResult when there's only distinct options that do not require any additional logic (i.e. making a custom MessageBox).
What I would do is to just send the DialogResult yourself on success:
private void btnOk_Click(object sender, EventArgs e)
{
if (allIsOK())
{
this.DialogResult = DialogResult.OK;
}
}
Consider tapping into the Forms's Closing event, and use the Cancel property of the event args to cancel form closing.
Here's a web page that discusses the idea; it's VB, but you'll get the idea:
http://www.vbinfozine.com/t_wfdlg.shtml
In Case you have used DialogResult on a button in a child Form (Which is a dialog), and want to return to form with no dialog result use a function on the form_closing() event:
private void ChildForm_FormClosing(object sender, FormClosingEventArgs e)
{
if (notValidated)
{
e.Cancel = true;
}
}
I have to handle both the single click and the double click of a button in a WPF application with different reaction.
Unfortunately, on a doubleclick, WPF fires two click event and a double click event, so it's hard to handle this situation.
It tried to solve it using a timer but without success...I hope you can help me.
Lets see the code:
private void delayedBtnClick(object statInfo)
{
if (doubleClickTimer != null)
doubleClickTimer.Dispose();
doubleClickTimer = null;
this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, new VoidDelegate(delegate()
{
// ... DO THE SINGLE CLICK ACTION
}));
}
private void btn_Click(object sender, RoutedEventArgs e)
{
if (doubleClickTimer == null)
doubleClickTimer = new Timer(delayedBtnClick, null, System.Windows.Forms.SystemInformation.DoubleClickTime, Timeout.Infinite);
}
}
}
private void btnNext_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
if (doubleClickTimer != null)
doubleClickTimer.Change(Timeout.Infinite, Timeout.Infinite); // disable it - I've tried it with and without this line
doubleClickTimer.Dispose();
doubleClickTimer = null;
//.... DO THE DOUBLE CLICK ACTION
}
The problem is that the 'SINGLE CLICK ACTION' called after the 'DOUBLE CLICK ACTION' on doubleclick. It's strange that I set thedoubleClickTimer to null on double click but in the delayedBtnClick it's true :O
I've already tried to use longer time, a bool flag and lock...
Do you have any ideas?
Best!
If you set the RoutedEvent's e.Handled to true after handling the MouseDoubleClick event then it will not call the Click Event the second time after the MouseDoubleClick.
There's a recent post which touches on having different behaviors for SingleClick and DoubleClick which may be useful.
However, if you are sure you want separate behaviors and want/need to block the first Click as well as the second Click, you can use the DispatcherTimer like you were.
private static DispatcherTimer myClickWaitTimer =
new DispatcherTimer(
new TimeSpan(0, 0, 0, 1),
DispatcherPriority.Background,
mouseWaitTimer_Tick,
Dispatcher.CurrentDispatcher);
private void Button_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
// Stop the timer from ticking.
myClickWaitTimer.Stop();
Trace.WriteLine("Double Click");
e.Handled = true;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
myClickWaitTimer.Start();
}
private static void mouseWaitTimer_Tick(object sender, EventArgs e)
{
myClickWaitTimer.Stop();
// Handle Single Click Actions
Trace.WriteLine("Single Click");
}
You could try this:
Button.MouseLeftButtonDown += Button_MouseLeftButtonDown;
private void Button_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
e.Handled = true;
if (e.ClickCount > 1)
{
// Do double-click code
}
else
{
// Do single-click code
}
}
If neccessary, you could require mouse click and wait until mouse up to perform the action.