WPF Combobox deriving from derived doesn't work

HOPEFULLY, someone strong in WPF knows what's going on... The scenario I've sampled below is also applicable to others too, like textbox, command buttons, etc...

I'm playing with creating custom user controls... Ex: working with a simple Combobox. In one project class library LibA I've created some samples derived from... ex: TextBox, ComboBox, Window, etc. A second library LibB I'm creating another class derived from ex: Combobox in LibA... Otherwise, no problem.... done similar thing in C# WinForms with no problems.

Now, the problem, I drag the control (from LibB) onto the first "Window" (native so no derivation issues) of the app, save and run. The derived library doesn't even hit its constructor which I just put a simple command just test it was getting created properly worked or not, but its not... In the XAML of the form, it is properly referencing both namespace projects, so I know that appears correct.

So, I then created a derived combobox in the same original LibA, put that on the form, and IT properly went into the constructor.

Here's a snippet of what I have going on.

namespace LibA
{
   public class MyCombo1 : ComboBox
   {
      public MyCombo1()
      {  ToolTip = "this is my base declaration"; } 
   }

   public class MyCombo1b : MyCombo1
   {
      public MyCombo1b() : base()
      {  ToolTip = "this constructor IS reached"; } 
   }
}

In a separate project (library),

using FirstLibraryThatHas_MyCombo1
namespace LibB
{
   public class OtherLibCombobox : MyCombo1
   {
      public OtherLibCombobox() : base()
      {  ToolTip = "this version is NOT being recognized in the window"; } 
   }
}

So, neither of these are visually designed, they are all in code only... In addition, I've done it with the TextBox control too, same results... It doesn't stop in the debugger... Any ideas?

Although I've changed actual names from sample, here's a brand new window, one with original class declaration AND one with the DERIVED version.. Here's a full XAML test window

<Window x:Class="MyProject.TestWindow"
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   Title="TestWindow" Height="300" Width="300" 
   xmlns:my="clr-namespace:WPFGUI;assembly=WPFGUI" 
   xmlns:my1="clr-namespace:DerivedControls;assembly=DerivedControls">

  <Grid>
    <my:MyComboBoxClass
        Name="MyComboBoxInWindow" 
        HorizontalAlignment="Left" 
        Height="23" 
        Width="120" />

    <my1:cboDerivedComboClass
        Name="cboDerivedComboInWindow" 
        Height="23" 
        HorizontalAlignment="Left" 
        Width="120" />
  </Grid>
</Window&g开发者_如何学JAVAt;

Isn't this making a circular reference?

You call MyDerivedControl that is in another assembly, and DerivedControl needs the primary assembly because it inherits a type you defined there. And then, you try to display it in a window from the primary assembly?

Try to clean and rebuild your project.

I've tried and failed to reproduce the problem. I think you have a different problem, though. If you use the xaml above - the number two combobox will completely cover the first - thus you will not be able to get the tooltip...

Also, check that all assemblies target the same framework version.