How do I programatically change a DockPanel in WPF?

Question

Note:By Request, I have added the full code for my XAML and xaml.cs files

In WPF, I have created a DockPanel like so:

<Window 
x:Class="RealEditor.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:forms="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
Title="RealEditor" Height="500" Width="700"
>
<DockPanel>
    <GridSplitter Grid.Column="1" Width="4" HorizontalAlignment="Left"/>
        <DockPanel x:Name="ftpDock" Grid.Row="1" Grid.Column="1"></DockPanel>
    </Grid>

</DockPanel>

I want to programmatically add a TreeView to the DockPanel, but in Window1.xaml.cs, I am unable to get the DockPanel by name, and add to it:

namespace RealEditor
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
  public partial class Window1 : Window
  {
    public Window1()
    {
      InitializeComponent();
      TreeViewItem mytreeView = new TreeViewItem();
      ftpDock.Children.Add(myTreeView);
    }
  }
}

The above code returns the following error:

"The name 'ftpDock' does not exist in the current context"

I am sure I have just missed something simple. Any ideas?

Answer 1

In your xaml, do you have the right class attribute for the window?

<Window x:Class="YourAssemblyName.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
            <DockPanel Grid.Row="1" x:Name="ftpDock" Grid.Column="1"></DockPanel>
    </Grid>
</Window>

See here: http://stackoverflow.com/questions/1503749/wpf-c-classes-textbox-and-reference-easy-does-not-exist-in-the-current-con

Answer 2

Firstly, your XAML is broken. You have an extra which is un-associated with opening Grid tag.

I just created a project, copied your XAML and Code behind in, and apart from the captilisation difference and fixing the extra tag, mine works fine.

My Full XAML:

<Window x:Class="WPFTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <DockPanel>
        <GridSplitter Grid.Column="1" Width="4" HorizontalAlignment="Left"/>
        <DockPanel x:Name="ftpDock" Grid.Row="1" Grid.Column="1"></DockPanel>
    </DockPanel>
</Window>

Code Behind:

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();

        TreeViewItem mytreeView = new TreeViewItem();
        ftpDock.Children.Add(mytreeView);
    }
}

Check all your tags and make sure you don't have any random extraneous tags floating around

Answer 3

Upon further testing and troubleshooting, I found that I was unable to reference any control added to Window1.xaml, not just the DockPanel. To fix the issue, I had to add "MSBuild:Compile" to the Custom Build field in the Window1.xaml File Properties.

I am unsure why that field was blank in my project, but hopefully this will help others experiencing the same "bug".