Can't set the data to a comboBox choice

it has been days I'm trying to create a comboBox with all available models. The code is this

for name , models in SortedPairs( player_manager.AllValidModels() ) do
   print("name: "..name.." model: "..models)
   custCbox:AddChoice(name , models , false)
end

I tried to print every name and model to know if I was wrong, but that's ok: name prints the display name and models prints the path. The OnSelect function is this:

custCbox.OnSelect = function( index, value, data )
   modelPanel:SetModel( data )
   print("Data " .. data)
   print("Value " .. value)
end

Data gives the display name and value gives a number. Why?

From the DComboBox documentation:

local cbox = vgui.Create( "DComboBox", BGPanel )

...

cbox:AddChoice( "Pink", Color( 255, 0, 255 ) )

function cbox:OnSelect( index, text, data )

    -- Set background panel color
    BGPanel:SetBackgroundColor( data )

end

Note the difference to your

custCbox.OnSelect = function( index, value, data )
   modelPanel:SetModel( data )
   print("Data " .. data)
   print("Value " .. value)
end

which is equivalent to

function custCbox.onSelect(index, value, data)
-- ...
end

And the example that uses the colon syntax.

function cbox:OnSelect(index, text, data)
end

is equivalent to

function cbox.OnSelect(self, index, text, data)
end

This difference causes a parameter shift by one. So what you think is index is actually your combobox, text is the selected index and data is the choices text.

Please read

Lua 5.4 Reference Manual: 3.4.10 Function Calls

Lua 5.4 Reference Manual: 3.4.11 Function Definitions

This is a very common mistake among beginners.