how to change xaml textbox dynamically?

Question

I made an enum for the state of the program. When it is set for JustInstalled, I am trying to change an XAML label's content using C#.

CS code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;

namespace WpfApplication3
{
    enum Status
    {
        JustInstalled, 
        Configured
    }
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
    public class Program
    {
        public static void Main()
        {
            Status status = new Status();
            if (!File.Exists("logindata.xml"))
            {
                status = Status.JustInstalled;
                if (status == Status.JustInstalled)
                {
                   Application.Current.Resources["loginlabel"].Content = "Please enter your desired username and password.";
                }
            }
        }
    }
}

XAML:

<Window x:Class="WpfApplication3.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:WpfApplication3"
        mc:Ignorable="d"
        Title="DFIHUDF" Height="350" Width="525"

        >
    <Grid>
        <Label FontSize="20" x:Name="label" Content="SFDGFDS" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="180,10,0,0" Width="209"/>
        <Label x:Name="loginlabel" Content="x" HorizontalAlignment="Left" Margin="84,95,0,0" VerticalAlignment="Top" Width="89"/>

    </Grid>
</Window>

The 2 errors were:

Error   CS1061  'object' does not contain a definition for 'Content' and no extension method 'Content' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?) WpfApplication3 C:\Users\Nathan\documents\visual studio 2015\Projects\WpfApplication3\WpfApplication3\MainWindow.xaml.cs    44

and

Error   CS0017  Program has more than one entry point defined. Compile with /main to specify the type that contains the entry point.    WpfApplication3 C:\Users\Nathan\documents\visual studio 2015\Projects\WpfApplication3\WpfApplication3\obj\Debug\App.g.i.cs  63

I have no idea what the errors are talking about, as I am new to WPF, and my main problem here is that I don't know how to dynamically change the content of a label with c#.

Answer 1

As I see you do not need to introduce additional stuffs like enums here, The following will sufice:

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

            if (!File.Exists("logindata.xml"))        
                StatusText = "Just Installed";  
            else
                StatusText = "Configured"; 


            DataContext = this; 
        }

    public string StatusText {get;set;}
}

Then your label:

<Label x:Name="loginlabel" Content="{Binding StatusText}" />

Answer 2

You need to have a mechanism to update the text when your StatusText property changes. This can be done by using a Dependency Property and binding.

First, put this binding in your XAML:

<Label x:Name="loginlabel" Content="{Binding StatusText}" />

Next, add a dependency property to your code so that the XAML will know about changes:

public static readonly DependencyProperty StatusTextProperty = 
DependencyProperty.Register("StatusText", typeof(string), typeof(Window1));

public string StatusText
{
    get
    {
        return this.GetValue(StatusTextProperty) as string;
    }
    set
    {
        this.SetValue(StatusTextProperty, value);
    }
}

Lastly, add a method to allow for the dynamic setting of the new status:

public void UpdateStatus()
{
    if (!File.Exists("logindata.xml"))
    {
        StatusText = "Please enter your desired username and password.";
    }
    else
    {
        StatusText = "Logged In";
    }
}

Answer 3

Try this:

public class Program
    {
        public static void Main()
        {
            WpfApplication3.MainWindow win = new WpfApplication3.MainWindow();
            Status status = new Status();
            if (!File.Exists("logindata.xml"))
            {
                status = Status.JustInstalled;
                if (status == Status.JustInstalled)
                {
                   win.loginlabel.Content = "Please enter your desired username and password.";

                }

                Application.Run(win);
            }
        }
    }