The variable is either undeclared or was never assigned warning

Question

I have code like this:

This is base class:

public class BaseClass : UserControl
{
     protected ListView list;
     protected TreeView tree;

     public BaseClass()
     {
         //...
     }
     //...
}

Child class

public partial class MyClass : BaseClass
{
     public MyClass()
     {
         InitializeComponent();
         this.BackColor = VisualStyleInformation.TextControlBorder;
         this.Padding = new Padding(1);
     }
     //...
}

partial class MyClass
{
    //...

    private void InitializeComponent()
    {
         this.tree = new System.Windows.Forms.TreeView();
         this.list = new System.Windows.Forms.ListView();
         //...
         this.tree.Location = new System.Drawing.Point(0, 23);
         this.tree.Name = "blablabla";
    }
}

And warnings:

Warning 1 The variable 'tree' is either undeclared or was never assigned.
Warning 2 The variable 'list' is either undeclared or was never assigned.

What am I doing wrong ? This variable are declared in base class, and assigned in child class.

Solution

This question lacks an answer, so here goes...

Rebuild Solution then restart Visual Studio worked for me :-)

Thanks to SLaks for his comment above.

Also discussed at:

stackoverflow.com - The variable 'variable_name' is either undeclared or was never assigned.

social.msdn.microsoft.com - The variable 'control_name' is either undeclared or was never assigned.