Ask user to save before closing then exit the winform application

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question

ravikumar-1532 asked Apr 26, '22 karenpayneoregon answered May 23, '22

Ask user to save before closing then exit the winform application

My below code should ask the user before closing the form, if no then exit the application itself.

 private void DataEntry_FormClosing(object sender, FormClosingEventArgs e)
     {
         try
         {
             String msg = "Confirm Save?";
             String caption = "Save Record";
             MessageBoxButtons buttons = MessageBoxButtons.YesNo;
             MessageBoxIcon ico = MessageBoxIcon.Question;
             DialogResult result;
             result = MessageBox.Show(this, msg, caption, buttons, ico);
             if (result == DialogResult.Yes)
             {
                 this.Validate();
                 this.tool_ManagementBindingSource.EndEdit();
                 this.tableAdapterManager.UpdateAll(this.pINQCDataSet);
                 MessageBox.Show("The Record saved Successfully", "Save_Update",
                     MessageBoxButtons.OK, MessageBoxIcon.Information);
    
             }
             else
             {
                 Application.Exit(); 
             }
         }
         catch (Exception ex)
         {
             MessageBox.Show("Saving Failed:" + ex.Message.ToString(), "Save",
                 MessageBoxButtons.OK, MessageBoxIcon.Error);
         }
     }

But I am getting message box appeared twice even after clicking no , then the below error appears , please guide me how to solve this problem.
@karenpayneoregon :pls help me.

windows-forms

image.png (12.2 KiB)

· 1

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Viorel-1 · Apr 26 at 06:42 PM

Try removing 'Application.Exit( )'.

Which line of the shown code gives the error dialog?

1 ·

Answer 1 · 2022-05-23T19:07:43.23Z

AkramElhayani-4441 answered May 23, '22 AkramElhayani-4441 commented May 23, '22

Use

 e.Cancel = true ;

instead of

 Application.Exit( )

then in FormClosed try call

   Application.ExitThread();

· 2

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Viorel-1 · May 23 at 07:33 PM

I think that FormClosed will not be called.

0 ·

AkramElhayani-4441 Viorel-1 · May 23 at 08:36 PM

it will be called if

 e.Cancel = true

was not called in code

0 ·

Answer 2 · 2022-05-23T20:53:05.727Z

karenpayneoregon answered May 23, '22

Greetings, I took an existing code sample, added code to detect changes and then prompt for exit without saving or save and close.

It uses MS-Access but does not matter as all that matters is the DataTable in the DataSet.

Source code

Form code

 using System;
 using System.ComponentModel;
 using System.Windows.Forms;
 using Access1.Classes;
 using static Access1.Classes.Dialogs;
    
 namespace Access1
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
             Closing += OnClosing;
         }
    
         private void OnClosing(object sender, CancelEventArgs e)
         {
             if (dataSet1.Tables[0].HasChanges())
             {
                 if (Question("Save before exiting"))
                 {
                     SaveChanges();
                 }
                 else
                 {
                     e.Cancel = false;
                 }
             }
               
         }
    
         private void personBindingNavigatorSaveItem_Click(object sender, EventArgs e)
         {
             SaveChanges();
         }
    
         private void SaveChanges()
         {
             Validate();
             personBindingSource.EndEdit();
             tableAdapterManager.UpdateAll(dataSet1);
         }
    
         private void Form1_Load(object sender, EventArgs e)
         {
             personTableAdapter.Fill(dataSet1.Person);
         }
     }
 }

MessageBox

 public static class Dialogs
 {
     public static bool Question(string text)
     {
         return (MessageBox.Show(
             text,
             Application.ProductName,
             MessageBoxButtons.YesNo,
             MessageBoxIcon.Question,
             MessageBoxDefaultButton.Button2) == DialogResult.Yes);
     }
 }

Detect changes (can be optimize, wrote it fast)

 public static class ExtensionMethods
 {
     public static bool HasChanges(this DataTable table)
     {
         var added = table.GetChanges(DataRowState.Added);
         if (added != null)
         {
             return true;
         }
    
         var deleted = table.GetChanges(DataRowState.Deleted);
         if (deleted != null)
         {
             return true;
         }
    
         var modified = table.GetChanges(DataRowState.Modified);
         if (modified != null)
         {
             return true;
         }
    
         return false;
     }
    
 }

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