Confirmation Box Code Error

Question

I'm setting up a confirmation box for clearing out a .txt file filled with raw data. Whether or not the action can complete is dependent on whether the "write data to file" box is checked- otherwise, you're going to try to delete something that doesn't exist. I'm getting an error:

Error 1 'System.Nullable<bool>' does not contain a definition for 'Yes' and no extension method 'Yes' accepting a first argument of type 'System.Nullable<bool>' could be found (are you missing a using directive or an assembly reference?)

while using this chunk of code:

private void reset_data_Click(object sender, RoutedEventArgs e)
        {
           
            if (MessageBox.Show("This operation will clear the .txt file. It cannot be undone.","Do you wish to continue?", MessageBoxButton.YesNo)==DialogResult.Yes)
                {

                }
            else if(chkOutput.IsChecked == false)
            	{
                	MessageBox.Show("No output file was created at the beginning of this program. This operation will have no effect");
            	}
        }	

It's not happy about the "DialogResult.Yes". How do I fix this? I saw this particular bit of code posted quite a bit on the web... it's a fairly simple operation, so what am I doing wrong?

Answer 1

The MessageBox.Show method in WPF returns a value of the MessageBoxResult enumeration, so instead of DialogResult.Yes you must use MessageDialogResult.Yes.

---

Marco Minerva [MCPD]
Blog: http://blogs.ugidotnet.org/marcom
Twitter: @marcominerva

Answer 2

That eliminates the error, but the error

Error 1 The name 'MessageDialogResult' does not exist in the current context

Appears in its place. I suppose I need to initialize this? Or is it some other issue?

Answer 3

I have confused the enumeration name the second time I have written it :-)

The correct value is MessageBoxResult.Yes.

---

Marco Minerva [MCPD]
Blog: http://blogs.ugidotnet.org/marcom
Twitter: @marcominerva

Answer 4

Use this:

            if (MessageBox.Show("Anwendung Beenden?", "Frage", MessageBoxButton.YesNo, MessageBoxImage.Warning) == MessageBoxResult.No)
            {
                textBlockEF00STZ1A.Text = "Beenden angeklickt";
            }
            else
            {
                this.Close();
            }

Best Regards

Bernd