Name does not exist in the namespace

Question

I am working on a simple UWP project using data template binding in VS 2015. When ever I try to specify the type for the Datatemplate I get an error.

XAML:

<Page x:Name="RootPage"
x:Class="Adaptive_News_Layout.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
xmlns:local="using:Adaptive_News_Layout"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" FontSize="22" >

 <SplitView x:Name="MySplitView" Grid.Row="1" DisplayMode="CompactOverlay" Background="LightGray" OpenPaneLength="200"  >
            <SplitView.Pane>
                <ListView x:Name="MyListview" ItemsSource="{x:Bind NavigationItems}"  >
                    <ListView.ItemTemplate>
                        <DataTemplate x:DataType="local:NavItem" >
                            <StackPanel Orientation="Horizontal">
                                <RelativePanel>
                                    <Button x:Name="Icon"  FontFamily="Segoe MDL2 Assets" Content="{x:Bind ButtonIcon}" Width="50" Height="50"/>
                                    <TextBlock x:Name="Section" Text="{x:Bind SectionTitle}" RelativePanel.RightOf="Icon" />
                                </RelativePanel>
                            </StackPanel>
                        </DataTemplate>
                    </ListView.ItemTemplate>

This is the class:

namespace Adaptive_News_Layout
{
    public class NavItem
    {
        public string ButtonIcon { get; set; }
        public string SectionTitle { get; set; }
    }
}

The error reads: The name "NavItem" does not exist in the namespace "using:Adaptive_News_Layout"

Woodchuck

how is "local" declared? – Parnell

Try building the solution see if there is any build error. And restart VS check if the error persist. – Jorgejorgensen

Same situation here, did you get this working? – Cuda

xmlns:local="using:Adaptive_News_Layout" – Woodchuck

These kinds of errors are so annoying and waste so much time >< – Determination

Answer 1

I figured out what the problem was. It's a glitch in Visual Studio 2015. After you add a namespace in XAML it's best to compile/ test run your program or you will get this problem. To fix it just:

1. Delete the namespace reference in question and all usages of that reference.
2. Perform a test run/ compile your program.
3. Add the namespace reference back into the opening page tag
4. Perform another test run/ compile your program.

Now when you use your new namespace reference the compiler won't glitch out.

Woodchuck

Still happening in VS2019. In my case the namespace existed but I hadn't compiled since I'd added new classes to it. Removed the offending XAML, compiled, re-added it and error went away. – Illailladvised

Answer 2

What worked for me was specifying the assembly in the namespace reference, that is: xmlns:the_namespace="clr-namespace:the_namespace" - produces the above error. xmlns:the_namespace="clr-namespace:the_namespace;assembly=the_assembly" - works well.

Olivia

Answer 3

I found that I had unintentionally defined the same object in a sub-namespace. once I got rid of the second definition, this problem disappeared

Ixia

Answer 4

You have to declare 'local' namespace in section which can be found on the top of ypur Xaml file. You will see many namespace with format xmlns:Name ="value" Add your name space with Name =local and Value as your Namespace

Queen

This is the opening page tag of my program: The "local" namespace is declared there '<Page x:Name="RootPage" x:Class="Adaptive_News_Layout.MainPage" xmlns="schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="schemas.microsoft.com/winfx/2006/xaml" xmlns:local="using:Adaptive_News_Layout" xmlns:d="schemas.microsoft.com/expression/blend/2008" xmlns:mc="schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" FontSize="22" >' – Woodchuck

The 5th line reads xmlns:local="using:Adaptive_News_Layout" – Woodchuck