I am working on a C# WPF application. After i get some input from the user i need to check some conditions and if the condition don't match and the user has pressed the X button I need to be able to show a MessageBox containing an error. After the user has pressed ok in the MessageBox i need the user to return to the previous window. My code looks something like this.

  private void Window_Closing(object sender, CancelEventArgs e)
  {
     MessageBoxResult closingMessegeBoxResult = MessageBox.Show("Is it OK to close?", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
     if (closingMessegeBoxResult != MessageBoxResult.OK)
     {
        e.Cancel = true;
        this.Activate();
     }
  }
     private void Window_Closed(object sender, EventArgs a)
  {

  }

For now i only want to be able to show the MessageBox with a random error.

CodePudding user response：

You should use the MessageBoxButton.OKCancel option to enable the user to avoid closing the window:

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
    MessageBoxResult closingMessegeBoxResult = MessageBox.Show("Is it OK to close?", "Error",
        MessageBoxButton.OKCancel, MessageBoxImage.Error);
    if (closingMessegeBoxResult != MessageBoxResult.OK)
    {
        e.Cancel = true;
    }
}

Using the above code, the window will only be closed when the user clicks the "OK" button of the dialog.

CodePudding user response：

Your code is working properly.

You have to add OnClosing event to the window,

And when you click on close of the window you will see the message

<Window x:Class="TestProject.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:TestProject"
    mc:Ignorable="d"
    Title="MainWindow" Height="450" Width="800"

    Closing="MainWindow_OnClosing">

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void MainWindow_OnClosing(object? sender, CancelEventArgs e)
    {
        MessageBoxResult closingMessegeBoxResult = MessageBox.Show("Is it OK to close?", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
        if (closingMessegeBoxResult == MessageBoxResult.OK)
        {
            e.Cancel = true;
            this.Activate();
        }
    }
}