Question

I’m making a bingo card generator to try and learn more about WPF, and having trouble figuring out how to set a labels content property to be set from a Property in my code-behind file.

I thought that I could use

<Setter Property="Content" Value="{Binding BNumber}">

for the content property to set the content of the label to a random element of my List<String>?

I have in my MainWindow.xaml

<Window x:Class="Bingo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="600" Width="800"
        WindowStartupLocation="CenterScreen">
  <Grid>
    <Grid Width="350" Height="420" ShowGridLines="True">
      <Grid.RowDefinitions>
        <RowDefinition Height="70"/>
        <RowDefinition Height="70"/>
        <RowDefinition Height="70"/>
        <RowDefinition Height="70"/>
        <RowDefinition Height="70"/>
        <RowDefinition Height="70"/>
      </Grid.RowDefinitions>
      <Grid.ColumnDefinitions>
        <ColumnDefinition Width="70" />
        <ColumnDefinition Width="70" />
        <ColumnDefinition Width="70" />
        <ColumnDefinition Width="70" />
        <ColumnDefinition Width="70" />
      </Grid.ColumnDefinitions>
      <!-- The Label I'm trying to set in this example -->
      <Label Grid.Column="0" Grid.Row="1" Style="{StaticResource BNumber}"
             FontSize="50" Width="70"/>
    </Grid>
  </Grid>
</Window>

My App.xaml code

<Application x:Class="Bingo.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
  <Application.Resources>
    <Style TargetType="Label" x:Key="BNumber">
      <Setter Property="Content" Value="{Binding}"></Setter>
      <Setter Property="Background">
        <Setter.Value>
          <SolidColorBrush Color="Beige"/>
        </Setter.Value>
      </Setter>
    </Style>
  </Application.Resources>
</Application>

In my MainWindow.xaml.cs I have this List<String> BNumbers object and a Property that returns a random element of the BNumbers List

public MainWindow() {
  InitializeComponent();
  BNumbers.Add("1");
  BNumbers.Add("2");
  BNumbers.Add("3");
  BNumbers.Add("4");
  BNumbers.Add("5");
  BNumbers.Add("6");
  BNumbers.Add("7");
  BNumbers.Add("8");
  BNumbers.Add("9");
  BNumbers.Add("10");
  BNumbers.Add("11");
  BNumbers.Add("12");
  BNumbers.Add("13");
  BNumbers.Add("14");
  BNumbers.Add("15");
}
public string RandomBNumber {
  get { return randomB(); }
}
public string randomB() {
  Random rand = new Random();
  int randomBNumber = rand.Next(0, 15);
  return BNumbers[randomBNumber];
}
public List<String> BNumbers = new List<string>();

Answer 1

In the constructor, you need to set the DataContext:

this.DataContext = this;

You’ll also need to change your setter to match the property name RandomBNumber :

<Setter Property="Content" Value="{Binding RandomBNumber }">