Why XAML giving errors? - wpf

Question

I making a prompter, white text on black background scrolling to end. The errors received do not break the program, but they are suspicious.
I got:
Warning RichTextBox,
Name='RichPrompterTextBox' Text.Length TextBlock.Text,
Name='CharacterCounterTextBlock' String Text property not found on
object of type RichTextBox. Warning RichTextBox,
Name='RichPrompterTextBox' MaxLength TextBlock.Text,
Name='CharacterCounterTextBlock' String MaxLength property not found
on object of type RichTextBox. Error null (0) TextBlock.Visibility,
Name='CharacterCounterTextBlock' Visibility Cannot find source:
RelativeSource FindAncestor,
AncestorType='System.Windows.Controls.TextBox', AncestorLevel='1'.
I have this XAML:
<Window x:Class="WpfDrawing.Prompter.PrompterView"
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:WpfDrawing.View"
xmlns:prompter="clr-namespace:WpfDrawing.Prompter" d:DataContext="{d:DesignInstance Type=prompter:PrompterViewModel}"
mc:Ignorable="d"
WindowState="Maximized"
WindowStyle="None"
Title="Prompter" Height="450" Width="800">
<RichTextBox
Background="Black"
Name ="prompterRichTextBox"
Foreground="White">
</RichTextBox>
</Window>
and this .cs:
/// <summary>
/// Interaction logic for Prompter.xaml
/// </summary>
public partial class PrompterView : Window
{
private readonly PrompterViewModel vm;
public PrompterView(PrompterViewModel vm)
{
this.vm = vm;
DataContext = vm;
InitializeComponent();
this.vm.PropertyChanged += Vm_PropertyChanged;
this.RichPrompterTextBox.MouseWheel += RichPrompterTextBox_MouseWheel;
this.RichPrompterTextBox.LayoutUpdated += RichPrompterTextBox_LayoutUpdated;
this.RichPrompterTextBox.TextChanged += RichPrompterTextBox_TextChanged;
SetToAdditionalMonitor();
}
private void SetToAdditionalMonitor()
{
var screens = Screen.AllScreens;
for (var i = 0; i != screens.Length; i++)
{
if (!screens[i].Primary)
{
this.WindowState = WindowState.Normal;
this.WindowStartupLocation = WindowStartupLocation.Manual;
this.Left = screens[i].Bounds.Left;
this.Top = screens[i].Bounds.Top;
this.Width = screens[i].Bounds.Width;
this.Height = screens[i].Bounds.Height;
}
}
}
private void RichPrompterTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
var textRange = new TextRange(this.RichPrompterTextBox.Document.ContentStart, this.RichPrompterTextBox.Document.ContentEnd);
vm.Text = textRange.Text;
}
private void RichPrompterTextBox_LayoutUpdated(object sender, System.EventArgs e)
{
vm.Height = this.RichPrompterTextBox.ViewportHeight + this.RichPrompterTextBox.ExtentHeight;
}
private void RichPrompterTextBox_MouseWheel(object sender, MouseWheelEventArgs e)
{
vm.ScrollPosition = RichPrompterTextBox.VerticalOffset;
}
private void Vm_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == nameof(vm.ScrollPosition))
{
this.RichPrompterTextBox.Dispatcher.Invoke(() => this.RichPrompterTextBox.ScrollToVerticalOffset(vm.ScrollPosition));
}
if(e.PropertyName == nameof(vm.Text))
{
var textRange = new TextRange(this.RichPrompterTextBox.Document.ContentStart, this.RichPrompterTextBox.Document.ContentEnd);
if (textRange.Text != vm.Text)
{
this.RichPrompterTextBox.Document = new FlowDocument(new Paragraph(new Run(vm.Text)));
}
}
}
private void Reset(object sender, RoutedEventArgs e)
{
vm.Reset();
}
private void StartStop(object sender, RoutedEventArgs e)
{
vm.RunStop();
}
private void CloseWindow(object sender, RoutedEventArgs e) => Close();
}
Xaml errors:
errors
I didn't bind anything, but I get binding errors.

Answer 1

These errors are not related to the code you've posted.
In your program you have bindings because these errors are indeed binding errors, where it seems that:
you're binding the Text property of the instance CharacterCounterTextBlock (of type TextBlock ) to a property named Text.Length of an instance of type RichTextBox named prompterRichTextBox. But the type RichTextBox doesn't have that propery.
you're binding the Text property of the instance CharacterCounterTextBlock (of type TextBlock ) to a property named MaxLength of an instance of type RichTextBox named prompterRichTextBox. But the type RichTextBox doesn't have that propery.
you're binding the Visibility property of the instance CharacterCounterTextBlock (of type TextBlock ) to something that's null because is not found in the source declaration.
More generally speaking, you shouldn't ask questions to solve specific issues related to bugs in your code, but if it's the case, please try to replicate the issue in a GitHub project (or similar public repositories), so that it's easier to understand the code you've used and find the cause.