WPF Can't find namespace

Question

So today i started my WPF .net framework project again. But it start of with a problem

Error CS0234 The type or namespace name 'Pages' does not exist in the namespace.

But this is strange because yesterday i had no problem, and if i try to start it anyway ignoring the error it will start normally en everything works.

So how can i stop getting this error message? because the program works. And the folder Pages exists

ZendersPage.xaml

<Page x:Class="Kraeken_en_Krønen_HKS_FO.ZendersPage"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  xmlns:local="clr-namespace:Kraeken_en_Krønen_HKS_FO"
  mc:Ignorable="d" 
  d:DesignHeight="720" d:DesignWidth="1080"
  Title="ZendersPage"
  xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
  TextElement.Foreground="{DynamicResource MaterialDesignBody}"
  TextElement.FontWeight="Regular"
  TextElement.FontSize="13"
  TextOptions.TextFormattingMode="Ideal"
  TextOptions.TextRenderingMode="Auto"
  Background="#FF3F3F46"
  FontFamily="{DynamicResource MaterialDesignFont}">

<Grid Background="#FF3F3F46">
    <Grid.RowDefinitions>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="auto"/>
    </Grid.RowDefinitions>

    <Grid Grid.Row="0">
        <StackPanel Margin="10,10,10,0">
            <materialDesign:Card Background="#FF3F3F46">
                <StackPanel Orientation="Vertical">
                    <Label Content="Zender toevoegen" FontSize="20px" Foreground="White" Margin="10,0,0,0"/>

                    <Label Content="Zender" Foreground="White" FontSize="20px" Margin="10,20,0,0"/>
                    <TextBox Foreground="White" FontSize="20px" Background="#FF62626A" Height="30px" Margin="10,0,0,0" x:Name="NewZenderNaam"/>

                    <Label Content="Omschrijving" Foreground="White" FontSize="20px" Margin="10,20,0,0"/>
                    <TextBox Foreground="White" FontSize="20px" Background="#FF62626A" Height="30px" Margin="10,0,0,0" x:Name="NewZenderOmschrijving"/>

                    <Button HorizontalAlignment="Left" Margin="10,20,0,10" Click="CreateNewZender" >
                        <StackPanel Orientation="Horizontal">
                            <materialDesign:PackIcon Kind="SendOutline" Width="20px" Height="25px"/>
                            <Label VerticalAlignment="Center" FontSize="15px" Foreground="#DDFFFFFF">Toevoegen</Label>
                        </StackPanel>
                    </Button>

                </StackPanel>
            </materialDesign:Card>
        </StackPanel>
    </Grid>

    <Grid Grid.Row="0" Grid.RowSpan="4">
        <WrapPanel x:Name="WijzigZenderPanel" Panel.ZIndex="205"/>
    </Grid>

    <Grid Grid.Row="1" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender" HorizontalAlignment="Center"/>
    </Grid>

    <Grid Grid.Row="2" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender1" HorizontalAlignment="Center"/>
    </Grid>

    <Grid Grid.Row="3" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender2" HorizontalAlignment="Center"/>
    </Grid>

    <Grid Grid.Row="4" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender3" HorizontalAlignment="Center"/>
    </Grid>

    <Grid Grid.Row="4" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender4" HorizontalAlignment="Center"/>
    </Grid>

    <Grid Grid.Row="4" VerticalAlignment="Top" HorizontalAlignment="Center">
        <WrapPanel x:Name="ExtraZender5" HorizontalAlignment="Center"/>
    </Grid>

</Grid>

using Kraeken_en_Krønen_HKS_FO.Pages;
using Kraeken_en_Krønen_HKS_FO.UserControls;
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;

namespace Kraeken_en_Krønen_HKS_FO
{
    /// <summary>
    /// Interaction logic for ZendersPage.xaml
    /// </summary>
/// 

class ZenderInformation
{
    private static string ZenderTitel = "";

    public static string ZenderTitelText
    {
        get { return ZenderTitel; }
        set { ZenderTitel = value; }
    }

    private static string ZenderOmschrijving = "";

    public static string ZenderOmschrijvingText
    {
        get { return ZenderOmschrijving; }
        set { ZenderOmschrijving = value; }
    }

    private static int i = 0;

    public static int y
    {
        get { return i; }
        set { i = value; }
    }

    private static int ZenderCount = 0;

    public static int ZenderCounter
    {
        get { return ZenderCount; }
        set { ZenderCount = value; }
    }
}

public partial class ZendersPage : Page
{
    Zenders zendersClass = new Zenders();

    int gridCount = 0;
    int totalCount;

    public ZendersPage()
    {
        InitializeComponent();
        try
        {
            zendersClass.GetAllChannels();
            PlaceZendersInGrid();
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }

    private void CreateNewZender(object sender, RoutedEventArgs e)
    {
        try
        {
            if (NewZenderNaam.Text != string.Empty && NewZenderOmschrijving.Text != string.Empty)
            {
                ZenderInformation.ZenderTitelText = NewZenderNaam.Text;
                ZenderInformation.ZenderOmschrijvingText = NewZenderOmschrijving.Text;
                zendersClass.UpdateDbWithNewZenders();
                ExtraZender.Children.Clear();
                ExtraZender1.Children.Clear();
                ExtraZender2.Children.Clear();
                ExtraZender3.Children.Clear();
                ExtraZender4.Children.Clear();
                ExtraZender5.Children.Clear();
                PlaceZendersInGrid();
                NewZenderNaam.Text = String.Empty;
                NewZenderOmschrijving.Text = String.Empty;
            }
            else
            {
                MessageBox.Show("Geen zender informatie ingevoerd");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }

    public void PlaceZendersInGrid()
    {
        try
        {
            zendersClass.GetAllChannels();

            foreach (var zender in ZenderNames.MusicZenders)
            {
                ZenderInformation.ZenderCounter++;
            }
            while (gridCount < ZenderInformation.ZenderCounter)
            {
                if (gridCount <= ZenderInformation.ZenderCounter)
                {
                    for (ZenderInformation.y = 0; ZenderInformation.y < 3; ZenderInformation.y++)
                    {
                        NewZenderLayout newZenderLayout = new NewZenderLayout();
                        newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                        newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                        newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                        ExtraZender.Children.Add(newZenderLayout);
                        totalCount = gridCount + 1;
                        gridCount = totalCount;
                    }
                    if (gridCount <= ZenderInformation.ZenderCounter)
                    {
                        for (ZenderInformation.y = 3; ZenderInformation.y < 6; ZenderInformation.y++)
                        {
                            NewZenderLayout newZenderLayout = new NewZenderLayout();
                            newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                            newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                            newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                            ExtraZender1.Children.Add(newZenderLayout);
                            totalCount = gridCount + 1;
                            gridCount = totalCount;
                        }
                        if (gridCount <= ZenderInformation.ZenderCounter)
                        {
                            for (ZenderInformation.y = 6; ZenderInformation.y < 9; ZenderInformation.y++)
                            {
                                NewZenderLayout newZenderLayout = new NewZenderLayout();
                                newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                                newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                                newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                                ExtraZender2.Children.Add(newZenderLayout);
                                totalCount = gridCount + 1;
                                gridCount = totalCount;
                            }
                            if (gridCount <= ZenderInformation.ZenderCounter)
                            {
                                for (ZenderInformation.y = 9; ZenderInformation.y < 12; ZenderInformation.y++)
                                {
                                    NewZenderLayout newZenderLayout = new NewZenderLayout();
                                    newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                                    newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                                    newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                                    ExtraZender3.Children.Add(newZenderLayout);
                                    totalCount = gridCount + 1;
                                    gridCount = totalCount;
                                }
                                if (gridCount <= ZenderInformation.ZenderCounter)
                                {
                                    for (ZenderInformation.y = 12; ZenderInformation.y < 15; ZenderInformation.y++)
                                    {
                                        NewZenderLayout newZenderLayout = new NewZenderLayout();
                                        newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                                        newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                                        newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                                        ExtraZender4.Children.Add(newZenderLayout);
                                        totalCount = gridCount + 1;
                                        gridCount = totalCount;
                                    }
                                    if (gridCount <= ZenderInformation.ZenderCounter)
                                    {
                                        for (ZenderInformation.y = 15; ZenderInformation.y < 18; ZenderInformation.y++)
                                        {
                                            NewZenderLayout newZenderLayout = new NewZenderLayout();
                                            newZenderLayout.NewZender.Text = ZenderNames.MusicZenders[ZenderInformation.y].ToString();
                                            newZenderLayout.NewOmschrijving.Text = ZenderNames.Musicdescription[ZenderInformation.y].ToString();
                                            newZenderLayout.Name = "zender" + ZenderNames.ZendersId[ZenderInformation.y];
                                            ExtraZender5.Children.Add(newZenderLayout);
                                            totalCount = gridCount + 1;
                                            gridCount = totalCount;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
}

}

Answer 1

You don't have a namespace called Kraeken_en_Krønen_HKS_FO.Pages . By convention, namespace structures usually match folder structures, but it's not automatic.

To make them match here you need to change namespace in your .xaml.cs file to:

namespace Kraeken_en_Krønen_HKS_FO.Pages
{
   ...

and then in your .xaml file you need to make the change in two places:

<Page x:Class="Kraeken_en_Krønen_HKS_FO.Pages.ZendersPage"         <--HERE
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  xmlns:local="clr-namespace:Kraeken_en_Krønen_HKS_FO.Pages"       <--HERE

Alternatives you could just remove the .Pages from the line where the error occurs, but in the long term this may cause confusion as you're breaching conventions.