Binding Header Text In A Custom Header Template

Question

I am having an issue binding header in a HeaderTemplate. When I do the following in xaml, this textblock either doesn't appear or there is no text shown in it making it invisible:

<TextBlock Text="{Binding}" Foreground="Red" HorizontalAlignment="Left" />

When working correctly it should show the header text which would be: "Name".

Xaml

<TextBox x:Name="NameTextBox" Header="Name" PlaceholderText="Enter Name" PlaceholderForeground="Gray"  IsColorFontEnabled="True" Text="{x:Bind ViewModel.Supplier.Name, Mode=TwoWay}">
    <TextBox.HeaderTemplate >
        <DataTemplate x:DataType="models:Supplier">
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding}" Foreground="Red" HorizontalAlignment="Left" />
            <SymbolIcon Symbol="ReportHacked" Foreground="Red" Visibility="{x:Bind HasErrors, Mode=OneWay}" HorizontalAlignment="Right" Margin="0 4">
                <ToolTipService.ToolTip>
                    <TextBlock Text="{x:Bind Errors, Mode=OneWay}" Foreground="Red" />
                </ToolTipService.ToolTip>
            </SymbolIcon>
            </StackPanel>
        </DataTemplate>
    </TextBox.HeaderTemplate>
</TextBox>

View Model

public partial class SupplierViewModel: ObservableValidator
{
    RecipeDBContext context;

    private Supplier _supplier = new Supplier();
    public Supplier Supplier => _supplier;

    [ObservableProperty]
    private ObservableCollection<Supplier> _suppliers;
}

Model

public partial class Supplier: ObservableValidator
{
    public int Id { get; set; }
    
    [ObservableProperty]
    [NotifyDataErrorInfo]
    [Required(ErrorMessage = "Name is Required")]
    [MinLength(2, ErrorMessage = "Name should be longer than one character")]
    private string _name = string.Empty;            
}

Answer 1

You are passing a string "Name" as the Header. If you want to have access to the Supplier value, you need to pass it to the Header:

<TextBox
    x:Name="NameTextBox"
    Header="{x:Bind ViewModel.Supplier.Name, Mode=OneWay}"
    Text="{x:Bind ViewModel.Supplier.Name, Mode=TwoWay}"
    ...>
    <TextBox.HeaderTemplate>
        <DataTemplate x:DataType="models:Supplier">
        </DataTemplate>
    </TextBox.HeaderTemplate>
</TextBox>