保存RichTextBox的文本

Question

I could do this easily in code-behind but don't want to break the MVVM pattern.

I have a RichTextBox and a 'Save' Button in my View. I want to save the contents of the RichTextBox to a file on the Save button click.

I have written a delegate class which expects a method to return void and have a single object parameter. I did this because I couldn't use the System.Action delegate.

class BtnCommandParameterised : ICommand
{
    public delegate void ActionParameterised(object rtb);

    private ActionParameterised _actionParameterised;
    public object _object;


    public BtnCommandParameterised(ActionParameterised   BtnCommandParameterisedActionParameterised)                      
    {
        _actionParameterised = BtnCommandParameterisedActionParameterised;
    }

    public bool CanExecute(object parameter)
    {
        return true;
    }

    public void Execute(object parameter)
    {
        _actionParameterised.Invoke(_object);
    }

    public event EventHandler CanExecuteChanged;
}

Then in my ViewModel I have an InitialiseBtnCommands() method which is called from the constructor. This initializes the command:

  private void InitialiseBtnCommands()
    {
        ReturnTextAsStringCommand = new      BtnCommandParameterised(ReturnTextAsStringCommandAction);
    }

This invokes my method to save the file.

 private void ReturnTextAsStringCommandAction(object Document)
    {
        TextRange range;
        FileStream fileStream;

        range = new TextRange(((FlowDocument)Document).ContentStart,
                              ((FlowDocument)Document).ContentEnd);

        fileStream = new FileStream(FileName, FileMode.Create);
        range.Save(fileStream, DataFormats.Text);
        fileStream.Close();
        Xceed.Wpf.Toolkit.MessageBox.Show("Text File Saved");
    }

Finally, in the View XAML, this is my binding:

  <Grid Name="MainGrid" DataContext="{StaticResource EditorViewModel}">
    <xctk:RichTextBox  SpellCheck.IsEnabled="True" HorizontalAlignment="Center"  Margin="206,166,206,60" Name="richTextBoxArticleBody" AcceptsTab="True" BorderBrush="Silver" BorderThickness="1" VerticalAlignment="Center"  Height="306" Width="600" FontFamily="Arial"/>
    <Button Command="{Binding ReturnTextAsStringCommand}" CommandParameter="{Binding ElementName=richTextBoxArticleBody, Path=Document}" Content="Save Article Text" Height="23" HorizontalAlignment="Left" Margin="703,478,0,0" Name="button1" VerticalAlignment="Top" Width="103" />
</Grid>

The command is being called and my method is invoked but nothing is passed into the ReturnTextAsStringCommandAction method?

I'm new to MVVM, finding things shall we say, a little confusing.

Answer 1

You're passing _object into the invoke method. I think you're meaning to pass parameter.

public void Execute(object parameter)
{
    _actionParameterised.Invoke(parameter);
}