Add Multiline Text with Enhance Rich option in Clintobject Model

Create Multiline Text

Field styleField = list.Fields.AddFieldAsXml("", true, AddFieldOptions.DefaultValue);
FieldMultiLineText fieldMultiLineText = context.CastTo(styleField);
fieldMultiLineText.RichText = true;
fieldMultiLineText.AllowHyperlink = true;
fieldMultiLineText.UpdateAndPushChanges(true);
list.Update();
context.ExecuteQuery();


Create Multiline Text with ich text option
Field styleField = list.Fields.AddFieldAsXml("", true, AddFieldOptions.DefaultValue);
FieldMultiLineText fieldMultiLineText = context.CastTo(styleField);
fieldMultiLineText.RichText = true;
fieldMultiLineText.AllowHyperlink = true;
fieldMultiLineText.UpdateAndPushChanges(true);
list.Update();
context.ExecuteQuery();


created Enhanced rich text column and use the SchemaXML to generate the new field:

Field rtfField = list.Fields.AddFieldAsXml("" , true, AddFieldOptions.DefaultValue);
rtfField.UpdateAndPushChanges(true);list.Update();
context.ExecuteQuery();


RestrictedMode=\"TRUE\" RichText=\"TRUE\" RichTextMode=\"FullHtml\"