I haven't used this attribute yet, but I'm planning to. If you use the overload of the attribute that you showed:

[ToolboxBitmap(typeof(myControl), "myBitmap.bmp")

you don't have to retrieve the embedded resource (but you *do* need to imbed the .bmp in the resource to begin with). In your example, this would be an image imbedded into the project that contains the class "myControl".

You could also use .NET's images for certain controls as well. For example, suppose I have my own TextBox subclass. If add this to the ToolBox, as is, I get the same default image, which looks like a gear-shape. If I want the image to look like the regular image for a TextBox, then I use the attribute this way:

[ToolboxBitmap(typeof(System.Windows.Forms.TextBox)]
public class MyTextBox : System.Windows.Forms.TextBox
{
}

Here's what the documentation has to say about the constructor for your original example:


Constructor
public ToolboxBitmapAttribute (Type t, string name)

Remarks
This constructor searches for an embedded resource in the assembly that defines the type specified by the t parameter. The constructor searches for a resource named namespace.name, where namespace is the namespace containing the definition of the class specified by the t parameter. For example, suppose that ControlA is a class in NamespaceA in AssemblyA.dll and that you passed "MyBitmap.bmp" to the name parameter. Then the constructor searches AssemblyA.dll for a resource named NamespaceA.MyBitmap.bmp.

Example
'The following code example demonstrates how to use the ToolboxBitmapAttribute constructor to set StopSignControl2.bmp as a toolbox icon for the StopSignControl2. This example assumes the existence of a 16-by-16-pixel bitmap named StopSignControl2.bmp with its BuildAction property set to EmbeddedResource.


~~Bonnie