I am creating a small project using winforms + c#, I have an issue in that I am using a second form in my project as a dialogue box. When the user attempts to close this I'd like to provide them with a confirmation screen to prevent any data loss in closing the form. This dialogue box form will also feature a 'home' button, closing the dialogue box form leaving them with the main window again. The problem arises when the windows X button is pressed at the top of the screen requiring me to set up an 'on form close' event to manage. This however creates an infinite loop with my current code shown below. Is there any way to avoid this?
private void frmCreateRoute_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult Safe_to_exit_check = MessageBox.Show("Are you sure you would like to go to the home screen? \n(Any entered data will be lost.)", "", MessageBoxButtons.YesNo);
if (Safe_to_exit_check == DialogResult.Yes)
{
this.Close();
}
}
and a simple:
private void Home_button_Click(object sender, EventArgs e)
{
this.Close();
}
for the home button.
Thanks
In your FormClosing, set:
e.Cancel = true;
to prevent closing the form. Don't use this.Close() there.
You need to set e.Cancel=true if the user select any thing different than DialogResult.Yes, otherwise let the form close:
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
var result = MessageBox.Show("Are you sure you want to close the form?",
"Close", MessageBoxButtons.YesNoCancel);
if (result != System.Windows.Forms.DialogResult.Yes)
e.Cancel = true;
}
Related
I am creating a password window using Windows Form Designer, except the context is a little different. There are several input fields, and one of them is password protected. There is a "Change" button that spawns a new password window on top of the home window. The user enters a password attempt and presses "OK". I need a way to have the OK button check the password and then send a DialogResult.OK back to the home window, or display an "incorrect password" if the attempt is incorrect. This means I can't set the DialogResult to DialogResult.OK initially, so I'm not sure how to do this.
Currently I set the DialogResult to DialogResult.OK in the click event function, but obviously this sets it for the next click, not the current one, so the user has to press the OK button twice.
private void buttonOK_Click(object sender, EventArgs e)
{
string passwordAttempt = textBoxPassword.Text;
if( passwordAttempt.CompareTo("pass") == 0 )
{
this.buttonOK.DialogResult = System.Windows.Forms.DialogResult.OK;
}
}
One possible solution is to trigger a second event through the code (not sure how to do this). Or alternatively, is there a better way to do password windows I'm not thinking of in this situation?
Set the AcceptButton of the dialog to buttonOK (the OK button). You can do this either in code or designer.
Set the DialogResult of the dialog form, not the button.
Code:
this.AcceptButton = buttonOK;
...
private void buttonOK_Click(object sender, EventArgs e)
{
string passwordAttempt = textBoxPassword.Text;
if (passwordAttempt.CompareTo("pass") == 0)
{
this.DialogResult = System.Windows.Forms.DialogResult.OK;
Close();
}
}
I have a WinForms application that checks for pending changes whenever the user hits the cancel button. If there are pending changes, I prompt the user to see if they are sure they wish to cancel. If they do, I close the form. If not, I just return. However, the form is closing anyways. After some debugging, I realized it was because this particular button is set to the form's CancelButton, so clicking it caused the form to close. To verify, I removed the CancelButton property, but the behavior persisted.
How can I prevent this automatic closing? Here is my event handler code:
private void closeButton_Click(object sender, EventArgs e)
{
DialogResult dr = DialogResult.Yes;
if (changesMade)
{
dr = MessageBoxEx.Show(this, "Are you sure you wish to disregard the changes made?", "Changes Made", MessageBoxButtons.YesNo);
}
if (dr == DialogResult.Yes)
{
Close();
}
else
{
//TODO:
}
}
In the above code, the form should only close if there are no changes made, or if the user chose to disregard them. I made changes, and clicked 'No' to the DialogBox, but the form still closed. With and without the button set as the form's CancelButton.
Just set the property DialogResult of the form to the enum DialogResult.None
....
if (dr == DialogResult.Yes)
{
Close();
}
else
{
this.DialogResult = DialogResult.None;
}
or simply:
if (dr != DialogResult.Yes)
this.DialogResult = DialogResult.None;
The form closes automatically because the property DialogResult of the button is not set to DialogResult.None in the Forms Designer. In this scenario, the WinForms engine takes that value and assign it to the DialogResult property of the whole form causing it to automatically close. This is usually used in the calling code of the form to distinguish between a Confirm and a Cancel button
In the example below suppose that on the frmCustomers there are two buttons, one with the DialogResult property set to DialogResult.OK and another set to DialogResult.Cancel. Now if the user hits the OK button you know, in the calling code what to do with the inputs for your new customer
using(frmCustomers f = new frmCustomers())
{
if(f.ShowDialog() == DialogResult.OK)
{
// Execute code to save a customer
}
}
Following up on my comment, this is what I do for an internal tool I wrote recently:
private void Form_FormClosing(object sender, FormClosingEventArgs e)
{
e.Cancel = !PromptUnsavedChanges();
}
private bool PromptUnsavedChanges()
{
if (HasFormChanged()) //checks if form is different from the DB
{
DialogResult dr = MessageBox.Show("You have unsaved changes. Would you like to save them?", "Unsaved Changes", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question);
if (dr == System.Windows.Forms.DialogResult.Yes)
tsmiSave_Click(null, null); // Saves the data
else if (dr == System.Windows.Forms.DialogResult.Cancel)
return false; // Cancel the closure of the form, but don't save either
}
return true; // Close the form
}
The logic could probably cleaned up from a readability point of view, now that I'm looking at it months later. But it certainly works.
With this you simply just call this.Close(); in your button click event. Then that event is what handles the prompting and decides if it should actually close or not.
Yes, noob question. My apologies.
When users click on the red x button on the window, I want to pop up a message asking if they really would want to quit. I found a similar question on this site: Override standard close (X) button in a Windows Form.
The thing is, I want to customize the font and the MessageBoxIcon for the MessageBox, and sadly it can't be done (or will take a lot of effort to be done). So, I've decided to make my own form.
protected override void OnFormClosing(FormClosingEventArgs e)
{
if (txtID.Text != "" || txtPassword.Text != "")
{
base.OnFormClosing(e);
if (e.CloseReason == CloseReason.WindowsShutDown) return;
// Confirm user wants to close
new formConfirmExit().ShowDialog();
}
}
I added this code under the main form. However, when I run my code and I click on the standard close button, my pop up (the custom form I did) doesn't do what it's job. Suppose I click the "No" button, it terminates my entire program. With the "Yes" button, the pop-up shows up again, and then everything kinda stops (on Visual Studio) and ta-da! an exception.
BTW, these are the Yes and No button methods (from my Custom Form's class):
private void btnYes_Click(object sender, EventArgs e)
{
Application.Exit(); // terminate program (exception is in here)
}
private void btnNo_Click(object sender, EventArgs e)
{
this.Close(); // close this pop up window and go back to main window
}
Changing Application.Exit() to Environment.Exit(0) did the job for the Yes button, but my No button, well, terminates the program, still.
Edit: When I click on the Yes button, the pop-up/my custom form shows again (just one time). It'll stay on that state (I can click on the Yes button repeatedly yet nothing happens). The InvalidOperationException is thrown when I click the Yes button first (note the first sentence of this paragraph) then the No button.
Thank you.
Add this in your No_Click:
private void btnNo_Click(object sender, EventArgs e)
{
DialogResult = DialogResult.No;
}
Then, change your forms closing event to the following:
protected override void OnFormClosing(FormClosingEventArgs e)
{
if (txtID.Text != "" || txtPassword.Text != "")
{
base.OnFormClosing(e);
if (e.CloseReason == CloseReason.WindowsShutDown
|| e.CloseReason == CloseReason.ApplicationExitCall)
return;
// Confirm user wants to close
using(var closeForm = new formConfirmExit())
{
var result = closeForm.ShowDialog();
if (result == DialogResult.No)
e.Cancel = true;
}
}
}
First, it checks if the form isn't closing through Application.Exit(), this may be triggered from your other form, so it will not reshow the custom MessageBox.
Second, you create a using statement around your custom form. This way you can preserve the values. You then set the dialogresult to no, if the user doesn't want to cancel. If this is the case, set e.Cancel = true to stop from exiting.
Im playing about with some very simple windows forms. I have an event handler for a form close event that asks the user whether they want to save what they've typed:
private void closeNpForm(object sender, FormClosingEventArgs e)
{
if (!saveFlag)
{
if (MessageBox.Show("Do you want to save the text entered?", "Save Changes?", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
e.Cancel = true;
saveFlag = true;
writeToFile(this.allText.Text);
}
}
}
if the user clicks yes (indicating they do want to save their text) i call the writeToFile method, and also set a flag so as not to ask them to save again:
private void writeToFile(string text)
{
writer = new StreamWriter("inputdata.txt");
writer.Write(text);
writer.Close();
this.Close();
}
As far as i can see, the writeToFile method should close the form when its finished. But this isnt happening, when i run the writeToFile method, the form just stays open. Can anyone tell me what im doing wrong?
as i understand it, calling this.Close() should trigger a form closing event, calling my event handler, due to the flag now being true, the form should just close without a problem.
note, my parent class extends the Form class, so im just using this to refer to my form instance.
e.Cancel = true -- whoops. The event is told cancel (read: not close the window).
I suspect that because close() is being called from within the close event and there is some internal clobbering going on (either suppressed or the Cancel is propagated over, etc). Just clean up the code (saving to the file has nothing to do with closing the window although the file might be saved and the window closed from within a button event.)
Happy coding.
writing to file and closing the form are two different kinds of operations. you should not have this.Close() in your writeToFile method.
As pst says, by setting e.cancel to true, you are basically telling the CloseForm event to be cancelled, therefore it's not closing once it exits from the closeNpForm event handler.
After exiting closeNpForm, the form checks for the Cancel property of the event and will not actually proceed with closing itself.
Why are you cancelling the close event and then calling writeToFile that closes the form?
In addition to what #pst said, why are you setting Cancel = true if you don't want to cancel the closing of the form?
If you remove e.Cancel = true; and this.Close(); it should do what you want.
This works for me:
public class Form1 : Form
{
bool saveFlag;
private void Form1_Load(object sender, EventArgs ev)
{ FormClosing += closeNpForm;
}
private void closeNpForm(object sender, FormClosingEventArgs e)
{
if (!saveFlag)
{
if (MessageBox.Show("Do you want to save the text entered?", "Save Changes?", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
e.Cancel = true;
saveFlag = true;
this.Close();
}
}
}
}
I have a dialog that I show with <class>.ShowDialog(). It has an OK button and a Cancel button; the OK button also has an event handler.
I want to do some input validation in the event handler and, if it fails, notify the user with a message box and prevent the dialog from closing. I don't know how to do the last part (preventing the close).
You can cancel closing by setting the Form's DialogResult to DialogResult.None.
An example where button1 is the AcceptButton:
private void button1_Click(object sender, EventArgs e) {
if (!validate())
this.DialogResult = DialogResult.None;
}
When the user clicks button1 and the validate method returns false, the form will not be closed.
Given that you've specified you want a pop error dialog, one way of doing this is to move your validation into a OnClosing event handler. In this example the form close is a aborted if the user answers yes to the question in the dialog.
private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
// Determine if text has changed in the textbox by comparing to original text.
if (textBox1.Text != strMyOriginalText)
{
// Display a MsgBox asking the user to save changes or abort.
if(MessageBox.Show("Do you want to save changes to your text?", "My Application",
MessageBoxButtons.YesNo) == DialogResult.Yes)
{
// Cancel the Closing event from closing the form.
e.Cancel = true;
// Call method to save file...
}
}
}
By setting e.Cancel = true you will prevent the form from closing.
However, it would be a better design/user experience to display the validation errors inline (via highlighting the offending fields in some way, displaying tooltips, etc.) and prevent the user from selecting the OK button in the first place.
Don't use the FormClosing event for this, you'll want to allow the user to dismiss the dialog with either Cancel or clicking the X. Simply implement the OK button's Click event handler and don't close until you are happy:
private void btnOk_Click(object sender, EventArgs e) {
if (ValidateControls())
this.DialogResult = DialogResult.OK;
}
Where "ValidateControls" is your validation logic. Return false if there's something wrong.
You can catch FormClosing an there force the form to remain opened.
use the Cancel property of the event argument object for that.
e.Cancel = true;
and it should stop your form from closing.
This doesn't directly answer your question (other already have), but from a usability point of view, I would prefer the offending button be disabled while the input is not valid.
Use this code:
private void btnOk_Click(object sender, EventArgs e) {
if (ValidateControls())
this.DialogResult = DialogResult.OK;
}
The problem of it is that the user has to clic two times the buttons for closing the forms;
Just add one line in the event function
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e)
{
this->DialogResult = System::Windows::Forms::DialogResult::None;
}
I wish I had time to find a better example, but you would be much better off using the existing windows forms validation techniques to do this.
http://msdn.microsoft.com/en-us/library/ms229603.aspx
void SaveInfo()
{
blnCanCloseForm = false;
Vosol[] vs = getAdd2DBVosol();
if (DGError.RowCount > 0)
return;
Thread myThread = new Thread(() =>
{
this.Invoke((MethodInvoker)delegate {
picLoad.Visible = true;
lblProcces.Text = "Saving ...";
});
int intError = setAdd2DBVsosol(vs);
Action action = (() =>
{
if (intError > 0)
{
objVosolError = objVosolError.Where(c => c != null).ToArray();
DGError.DataSource = objVosolError;// dtErrorDup.DefaultView;
DGError.Refresh();
DGError.Show();
lblMSG.Text = "Check Errors...";
}
else
{
MessageBox.Show("Saved All Records...");
blnCanCloseForm = true;
this.DialogResult = DialogResult.OK;
this.Close();
}
});
this.Invoke((MethodInvoker)delegate {
picLoad.Visible = false;
lblProcces.Text = "";
});
this.BeginInvoke(action);
});
myThread.Start();
}
void frmExcellImportInfo_FormClosing(object s, FormClosingEventArgs e)
{
if (!blnCanCloseForm)
e.Cancel = true;
}
You can probably check the form before the users hits the OK button. If that's not an option, then open a message box saying something is wrong and re-open the form with the previous state.