C# – How to close WPF window (dialog box) when Enter key is pressed

cwpfwpf-controlswpfdatagridxaml

I have a WPF window which opens as a modal dialog.

On dialog, I have OK & Cancel buttons with IsDefault & IsCancel properties set to True for them respectively. Both the buttons have Click event handlers which close the dialog box.

Here is the relevant XAML:

<StackPanel Orientation="Horizontal" Grid.Row="1"  Height="45" VerticalAlignment="Bottom" HorizontalAlignment="Right" Width="190">
    <Button Content="OK"
                Height="25" Margin="10,10,10,10" Width="75" Name="btnOK" TabIndex="1600" IsDefault="True" Click="btnOK_Click"                       
                VerticalContentAlignment="Center" HorizontalContentAlignment="Center" />
    <Button Content="Cancel"
                Height="25" Margin="10,10,10,10" Width="75" Name="btnCancel" TabIndex="1700" IsCancel="True"
                VerticalContentAlignment="Center" HorizontalContentAlignment="Center" Click="btnCancel_Click" />
</StackPanel>

Here is the code behind:

private void btnOK_Click(object sender, RoutedEventArgs e)
{
    // My some business logic is here                
    this.Close();
}

private void btnCancel_Click(object sender, RoutedEventArgs e)
{
    this.Close();
}

When I press Esc button on the keyboard (even when focus is not on the Cancel button), the dialog box gets closed as expected. However, when I press Enter key when focus is NOT on the OK button, nothing happens.

I have a DataGrid on the dialog. I want to close the dialog when I select any row in the data grid and press enter.

How to make this thing happen?

Some additional information: I have a text box on the dialog. And it has the event handler for the Keyboard.PreviewKeyDown event. When I am in the text box and I press enter, the dialog box should not be closed. But I can remove this handler. Important thing is to get above question resolved.

private void tbxSearchString_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Enter)
    {
        this.Search(); // Does some searching
    }
}

Best Answer

Your code is working fine for me. it close dialog when I press enter. You can write e.Handled = true; line after your search functionality in tbxSearchString_PreviewKeyDown event. So it will not close dialog.

<Grid>
        <TextBox Name="tbxSearchString" HorizontalAlignment="Left" Width="100" Height="30" Grid.Row="0" PreviewKeyDown="tt_PreviewKeyDown"></TextBox>
        <StackPanel Orientation="Horizontal" Grid.Row="1"  Height="45" VerticalAlignment="Bottom" HorizontalAlignment="Right" Width="190">

            <Button Content="OK" 
                Height="25" Margin="10,10,10,10" Width="75" Name="btnOK" TabIndex="1600" IsDefault="True" Click="btnOK_Click"                        
                VerticalContentAlignment="Center" HorizontalContentAlignment="Center" />
            <Button Content="Cancel" 
                Height="25" Margin="10,10,10,10" Width="75" Name="btnCancel" TabIndex="1700" IsCancel="True" 
                VerticalContentAlignment="Center" HorizontalContentAlignment="Center" Click="btnCancel_Click" />
        </StackPanel>
    </Grid>

Code behind

private void btnOK_Click(object sender, RoutedEventArgs e)
        {
            DialogResult = true; 
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            this.Close();
        }

        private void tbxSearchString_PreviewKeyDown(object sender, KeyEventArgs e)
        {
           if (e.Key == Key.Enter)
           {
               this.Search();
               e.Handled = true;
           }
        }

Related Solutions

Wpf – How does the WPF Button.IsCancel property work

Yes, it only works on dialogs as a normal window has no concept of "cancelling", it's the same as DialogResult.Cancel returning from ShowDialog in WinForms.

If you wanted to close a Window with escape you could add a handler to PreviewKeyDown on the window, pickup on whether it is Key.Escape and close the form:

public MainWindow()
{
    InitializeComponent();

    this.PreviewKeyDown += new KeyEventHandler(CloseOnEscape);
}

private void CloseOnEscape(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Escape)
        Close();
}

C# – How to hide close button in WPF window

WPF doesn't have a built-in property to hide the title bar's Close button, but you can do it with a few lines of P/Invoke.

First, add these declarations to your Window class:

private const int GWL_STYLE = -16;
private const int WS_SYSMENU = 0x80000;
[DllImport("user32.dll", SetLastError = true)]
private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

Then put this code in the Window's Loaded event:

var hwnd = new WindowInteropHelper(this).Handle;
SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);

And there you go: no more Close button. You also won't have a window icon on the left side of the title bar, which means no system menu, even when you right-click the title bar - they all go together.

Important note: all this does is hide the button. The user can still close the window! If the user presses Alt+F4, or closes the app via the taskbar, the window will still close.

If you don't want to allow the window to close before the background thread is done, then you could also override OnClosing and set Cancel to true, as Gabe suggested.

Best Answer

Code behind

Related Solutions

Wpf – How does the WPF Button.IsCancel property work

C# – How to hide close button in WPF window

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