Sharepoint > Which characters are *not* allowed in a list? - sharepoint

Question

I've tried looking this up and haven't come up with the answer I'm looking for; I've found what cannot be included in filenames, folder names, and site names... but nothing on actual fields in a list.
I noticed that the percent symbol (%) is one that's not allowed in files/sites/folders. But it also doesn't populate when I try to pro grammatically add the fields to the list. I am doing this by using a small C# application that sends the data via Sharepoint 2010's built-in web services. I can manually enter the character, but it messes up each field in the row if I try it through code.
I've tried some of the escape characters that I've found via Google (_x26), but these don't seem to work either. Has anyone else had an issue with this? If these characters are allowed, how can I escape them when sending the data through a web service call?
Thanks in advance!
Justin

Answer 1

Any characters that aren't allowed when you enter a field name get encoded in the internal name. The format is a little different to what you show - try "_x0026_".
I usually avoid issues with weird internal names by creating the field with no spaces or special characters in the name, then renaming it. When you rename a field, only the display name changes and you keep the simple internal name.

Answer 2

Characters not allowed in SharePoint file name:
~, #, %, & , *, {, }, \, :, <, >, ?, /, |, "
Pasted from http://chrisbarba.com/2011/01/27/sharepoint-filename-special-characters-not-allowed/

Answer 3

Am I saying something weird when I state that there usually is a reason for certain characters not being allowed. I don't know which or why, but there probably is a reason.
Since you control which fields need to be there you can also dictate their (internal) names. I'd say follow best practice and name your fields using Camel case. And because you created them, you can just map the fields to the according fields in your data source.

Answer 4

As a follow on to #Elisa's answer, here's some JavaScript / TypeScript code that helps to prevent users from uploading files into SharePoint with invalid characters in the file name implemented on Nintex forms.
Here's the gist of the JavaScript version (note you'll have to obviously adapt for your own needs since this was designed for Nintex) :
//------------------------------------------------------------------------
//JavaScript Version:
//Code from http://cc.davelozinski.com/tips-techniques/nintex-form-tips-techniques/javascript-typescript-for-nintex-forms-to-validate-file-names
//------------------------------------------------------------------------
function validateAttachmentNames(eventObject) {
var textbox$ = NWF$(this);
var attachrowid = this.id.substring(10, 47);
var fileUploadid = attachrowid;
var index = attachrowid.substring(36);
//console.log('index:' + index);
//console.log('attachrowid:' + attachrowid);
//console.log('fileUploadid:' + fileUploadid);
if (index == '') {
attachrowid += '0';
}
var fileName = NWF.FormFiller.Attachments.TrimWhiteSpaces(textbox$.val().replace(/^.*[\\\/]/, ''));
var match = (new RegExp('[~#%\&{}+\|]|\\.\\.|^\\.|\\.$')).test(fileName);
if (match) {
isValid = false;
setTimeout(function () {
NWF$("tr[id^='attachRow']").each(function () {
var arrParts = (NWF$(this).find(".ms-addnew")[0]).href.split('"');
var fileName = arrParts[5];
var attachRow = arrParts[1];
var fileUpload = arrParts[3];
var match = (new RegExp('[~#%\&{}+\|]|\\.\\.|^\\.|\\.$')).test(fileName);
if (match) {
console.log(fileName);
NWF.FormFiller.Attachments.RemoveLocal(attachRow, fileUpload, fileName);
alert('Invalid file: ' + fileName + ' You cannot attach files with the following characters ~ # % & * { } \ : < > ? / + | \n\nThe file has been removed.');
}
});
}, 500);
}
}