Repairing export failure

Added support for handling characters not allowed in MS Excel

app/views/admin/seminars/export.xlsx.axlsx

@@ -2,7 +2,12 @@
 
 wb = xlsx_package.workbook
 
-wb.add_worksheet(name: (@seminar.title.to_s[0..27]+'...')) do |sheet|
+illegal_chars = /[:\\\/\[\]\*\?]/
+
+sanitized_title = @seminar.title.to_s.gsub(illegal_chars, ' ').strip
+sheet_name = (sanitized_title[0..27] + '...').gsub(/\.{4,}/, '...')
+
+wb.add_worksheet(name: sheet_name) do |sheet|
 
   row = [t('seminar_signup.signup_time')]
 
@@ -35,6 +40,7 @@ wb.add_worksheet(name: (@seminar.title.to_s[0..27]+'...')) do |sheet|
       row << rf.title
     end
   end
+  
   highlight_style = wb.styles.add_style(
     :bg_color => 'ffeb3b',
     :b => true,
@@ -52,7 +58,7 @@ wb.add_worksheet(name: (@seminar.title.to_s[0..27]+'...')) do |sheet|
     row2 << "#{signup.display_serial_number}"
     row2 << "#{signup[:name]} "
     row2 << "#{signup.unit} "
-    row2 << "#{signup[:tel]} "
+    row2 << "#{signup.tel} "
     row2 << "#{signup[:phone]} "
     row2 << "#{signup[:fax]} "
     row2 << "#{signup.address} "
@@ -77,4 +83,3 @@ wb.add_worksheet(name: (@seminar.title.to_s[0..27]+'...')) do |sheet|
   end
 
 end
-