Write To Output message (C# => TextBox)

Question

I have TextBox:

 <TextBox  DockPanel.Dock="Bottom"               
           FontFamily="Consolas"
           Text="{Binding Path=Output}"
           VerticalScrollBarVisibility="Visible"
           HorizontalScrollBarVisibility="Auto"
           AcceptsReturn="True"
           AcceptsTab="True" />

To inside this TextBox I want to send some/add the message:

public string Output { get; set; }
public void WriteToOutput(string message)
{
 Output += DateTime.Now.ToString("dd.MM HH:mm:ss") + " " + message + Environment.NewLine;
}     

public void LoadExcelFile()
{
  WriteToOutput("Start....")
  //SOME CODE
  WriteToOutput("End....")
}

Output should looks like:

Start...
End...

But the text it's not showing into TextBox. What is the reason?

Update: my MainViewModel.cs:

[AddINotifyPropertyChangedInterface]
public class MainViewModel
{
....
}

I'm using PropertyChanged.Fody

OnPropertychanged. You need to implement INotifyPropertyChanged — Nawed Nabi Zada
– Nawed Nabi Zada, Commented Feb 25, 2019 at 13:40
is the propertychanged event raised? (hahahha the triple simultaneous answers) — iSpain17
– iSpain17, Commented Feb 25, 2019 at 13:40

zing · Accepted Answer · 2019-02-25 13:51:16Z

5

You're missing the INotifyPropertyChanged implementation.

A working example:

using System.ComponentModel;

public partial class MainWindow : Window, INotifyPropertyChanged
{
    private string output;
    public string Output
    {
        get { return output; }
        set
        {
            output = value;
            OnPropertyChanged(); // notify the GUI that something has changed
        }
    }

    public MainWindow()
    {
        this.DataContext = this;
        InitializeComponent();
        this.Loaded += MainWindow_Loaded;
    }

    private void MainWindow_Loaded(object sender, RoutedEventArgs e)
    {
        Output = "Hallo";
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
    {
        if (PropertyChanged != null) {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName: propertyName));
        }
    }
}

The XAML code would look like this:

<TextBox Text="{Binding Output}"/>

As you can see, whenever the Output property changes, the PropertyChanged event will be called. Every GUI Element that is bound to that Property will know that something has changed.

Note: [CallerMemberName] automatically gets the name of the property the method has been called with. If you don't want to use it, remove it. You'd have to change the OnPropertyChanged call to OnPropertyChanged("Output");, though.

edited Feb 25, 2019 at 13:51

zing

6306 silver badges15 bronze badges

answered Feb 25, 2019 at 13:45

devsmn

1,04012 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

4est Over a year ago

I have implemented [AddINotifyPropertyChangedInterface] public class MainViewModel

Mikael Dúi Bolinder Over a year ago

@4est have you added OnPropertyChanged to the setter?

4est Over a year ago

Im using PropertyChanged.Fody and I think I don't need it?

Collectives™ on Stack Overflow

Write To Output message (C# => TextBox)

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related