How to specify columns when adding new item to list using set_item

Question

I'm trying to add an item to a SharePoint list like so:

Title  |  Column1  |  Column2
-------+-----------+-----------
title1 |        1  |  a
title2 |        2  |  b

Now lets say I want to add

title3 |        3  | c

Using the following function:

var listColumnNames = ["Column1", "Column2"];

function addNewItem(title, columns) {

    var itemCreateInfo = new SP.ListItemCreationInformation();
    var newListItem = list.addItem(itemCreateInfo);

    // this works, it will create a new row with the title
    newListItem.set_item("Title", title); 

    // this throws the error below  
    newListItem.set_item("Column1", "test"); 

    // this does nothing
    newListItem["Column1"] = "test"; 

    // this is my ultimate goal, but also doesn't work
    for (var i = 0 ; i < listColumnNames.length ; i++)
        newListItem.set_item(listColumnNames[i], columns[i])

    newListItem.update();
    context.load(newListItem);
    context.executeQueryAsync(querySuccess, queryFailed);
}

But I get this error:

Column 'Column1' does not exist. It may have been deleted by another user. /MyPath/MyListName undefined

In this tutorial: http://adicodes.com/add-update-and-delete-list-items-using-ecmascript/

It omits the lines I need, but it seems like what I'm doing is the right idea:

newItem.set_item('Title', 'This is new item');

// set values to other columns of the list here

newItem.update();

In the docs: https://msdn.microsoft.com/en-us/library/office/hh185011(v=office.14).aspx

It shows doing something that looks like what I'm doing, but it doesn't clarify whether "Body" is actually the column name or some other attribute I'm unaware of.

oListItem.set_item('Title', 'My New Item!');

oListItem.set_item('Body', 'Hello World!');

oListItem.update();

Can anyone see what I'm doing wrong?

Answer 1

Make sure you are using field internal name.

You can find the field internal name by opening the List Settings. And then right click the field and copy the URL. Paste the URL in notepad and check the query string value for Field=