尝试使用 Name 索引 nil

Question

Im creating a script using remote functions, but at elseif part2.Name==selected.Name is says: "attempt to index nil with Name" here is the script:

 game.ReplicatedStorage.Events.PlaceBlock.OnServerInvoke= function(player,pos,selected)
        for i,part2 in ipairs(parts:GetChildren()) do
            if part2== nil then
                partPlace= parts.BasicPart
            elseif part2.Name==selected.Name then
                partPlace = selected:Clone()
            end
        end
        partPlace.CFrame = CFrame.new(math.ceil(pos.X), math.ceil(pos.Y)+2, math.ceil(pos.Z))
        partPlace.Orientation = Vector3.new(0,0,0)
        partPlace.Parent = player.Plate.Value.Parts
        partPlace.Owner.Value=player
    end

Answer 1

Your problem is probably, that selected is nil (maybe you forgot to pass a third argument when you called the function, or it was nil).

Answer 2

There are global variables in your code that are missing. This problem has been unsolved for a while. I would suggest though in this scenario that you break the loop once you have found the part in question. There is no need to check for a nil value in the loop, because all Instances from within another Instance are always going to be an Instance, and not nil .

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Events = ReplicatedStorage:WaitForChild("Events")
local PlaceBlock = Events:WaitForChild("PlaceBlock")

function PlaceBlock.OnServerInvoke(player: Player, position: Vector3, selected: BasePart)
    assert(typeof(player) == 'Instance' and player:IsA("Player"), "player must be a Player")
    assert(typeof(position) == 'Vector3', "position must be a Vector3")
    assert(typeof(selected) == 'Instance' and selected:IsA("BasePart"), "selected must be a BasePart")

    local placement

    for _, v in pairs(parts:GetChildren()) do
        if typeof(v) == 'Instance' and v.Name == selected.Name then
            placement = v:Clone()
            break
        end
    end

    if typeof(placement) ~= 'Instance' then
        placement = parts.BasicPart
    end

    placement.CFrame = CFrame.new(math.ceil(pos.X), math.ceil(pos.Y) + 2, math.ceil(pos.Z))
    placement.Orientation = Vector3.new(0, 0, 0)
    placement.Parent = player.Plate.Value.Parts
    placement.Owner.Value = player
end

Why I chose to solve this problem should not really be a concern, this has been left sitting around for quite a while.

I hope you've found your solution, regardless, while this solution is here for those who may be curious as to what the answer may be.