Creating site column and add it to content type

Question

I am using the below code

    Web rootWeb = clientContext.Site.RootWeb;    
    rootWeb.Fields.AddFieldAsXml("<Field DisplayName='Session Name' Name='SessionName' ID='"+new GUID()+"' Group='SharePoint Saturday 2014 Columns' Type='Text' />", false, AddFieldOptions.AddFieldInternalNameHint);
    clientContext.ExecuteQuery();
    Field session = rootWeb.Fields.GetByInternalNameOrTitle("SessionName");
    ContentType sessionContentType = rootWeb.ContentTypes.GetById("0x0100BDD5E43587AF469CA722FD068065DF5D");
    sessionContentType.FieldLinks.Add(new FieldLinkCreationInformation 
    {
        Field = session
    });
    sessionContentType.Update(true);
    clientContext.ExecuteQuery();

This creates a site column and adds it to the group, but when I try to attach it to a content type it throws

duplicate "SessionName" found

I also get the below error sometimes

The field specified with name "SessionName" and ID{some-id} is not accessible or does not exist

After creating site column using this code, I am not able to add site column to content type manually!!

It throws the same error

Answer 1

I have faced this issue before. The error says that there already exists a column named SessionName. Replace SessionName with SessionNameTest and try. Mostly this will solve your issue.

Answer 2

I removed the ID parameter in the column creation and it worked fine

  Web rootWeb = clientContext.Site.RootWeb;    
    rootWeb.Fields.AddFieldAsXml("<Field DisplayName='Session Name' Name='SessionName'  Group='SharePoint Saturday 2014 Columns' Type='Text' />", false, AddFieldOptions.AddFieldInternalNameHint);
    clientContext.ExecuteQuery();
    Field session = rootWeb.Fields.GetByInternalNameOrTitle("SessionName");
    ContentType sessionContentType = rootWeb.ContentTypes.GetById("0x0100BDD5E43587AF469CA722FD068065DF5D");
    sessionContentType.FieldLinks.Add(new FieldLinkCreationInformation 
    {
        Field = session
    });
    sessionContentType.Update(true);
    clientContext.ExecuteQuery();

Answer 3

But to be useful i guess you need to set name through a variable like

string columnName;
string groupName;

rootWeb.Fields.AddFieldAsXml("<Field DisplayName='"+columnName+"' Name='" + columnName + "' Group='" + groupName + "' Type='Text' />", false, AddFieldOptions.AddFieldInternalNameHint);

Then you can add it to a list

string listName;

List addColumnList = web.Lists.GetByTitle(listName);
Field newColumn = web.Fields.GetByInternalNameOrTitle(columnName);
addColumnList.Fields.Add(newColumn);
context.ExecuteQuery();