Unable to delete Hidden column from the list using CSOM in sharepoint online

Question

I am unable to delete the hidden columns (IconOverlay) from the document library using CSOM. At the time of provisioning, the IconOverlay column was added to content type and content type is associated with the document library.

Now I have to remove that column from the document library, so first, I am removing the column from the content type and I am successful in doing that but when it comes to removing the orphan IconOverlay column from the document library, it is throwing an exception "You can not delete hidden column". Any help will be appreciated.

Answer 1

Here's a solution working in SPServer, but CSOM.

The idea is to change the field schema's CanToggleHidden property.

You should adapt it slightly to get the library field, not the site field.

This is way verbose, you could probably do this in 2 lines of code :p

Hope it helps.

public void TryMakeColumnVisible()
{
    //params
    string url = "http://yoursite";
    string fieldTitle = "test_column_number";
    bool hidden = false;
    bool canToggle = true;

    ConsoleExtensions.WriteWarning("Checking column hidden...");
    context = new ClientContext(url);
    context.Credentials = new System.Net.NetworkCredential(UserName, Password, Domain);

    Web web = context.Web;
    context.Load(web);
    context.ExecuteQuery();

    Field field = web.Fields.GetByTitle(fieldTitle);
    context.Load(field);
    context.ExecuteQuery();

    string canToggleCurrent = Regex.Replace(field.SchemaXml, ".*CanToggleHidden=\"(.*?)\".*", "$1");

    string newSchemaXml = Regex.Replace(field.SchemaXml, "CanToggleHidden=\"" + canToggleCurrent + "\"", "CanToggleHidden=\"" + canToggle.ToString().ToUpper() + "\"");

    Console.WriteLine("Field          : " + field.Title);
    Console.WriteLine("Hidden         : " + field.Hidden);
    Console.WriteLine("CanToggleHidden: " + canToggleCurrent);
    Console.WriteLine(field.SchemaXml);

    //without this --> Unhandled Exception: Microsoft.SharePoint.Client.ServerException: Cannot change Hidden attribute for this field
    //update schema to allow update hidden property
    field.SchemaXml = newSchemaXml;
    field.Update();
    context.ExecuteQuery();

    //update hidden property
    field.Hidden = hidden;
    field.Update();
    context.ExecuteQuery();

    Console.WriteLine(Environment.NewLine + "Setting " + fieldTitle + " with Hidden " + hidden + " and CanToggleHidden " + canToggle);
    Console.WriteLine("Hidden         : " + field.Hidden);
    Console.WriteLine(newSchemaXml);
}