Changing the font in a Revit file

FontChangingCommand.cs

using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Input;

namespace EEPRevitPlagin.EEPRPCommandModules.FontChanging
{
    [Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    internal class FontChangingCommand : IExternalCommand
    {

        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            UIApplication uiApp = commandData.Application;
            Document doc = uiApp.ActiveUIDocument.Document;

            try
            {
                LanguageChangeCommandWPF window = new LanguageChangeCommandWPF(doc);
                window.ShowDialog();
                return Result.Succeeded;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
                return Result.Cancelled;
            }
        }
        public void TextNoteMethod(StyleTextDictionary[] styles, Document doc, string choiceFont)
        {
            using (Transaction tran = new Transaction(doc, "Changing Font"))
            {
                tran.Start();

                ICollection<Element> textType =
                    new FilteredElementCollector(doc).OfClass(typeof(TextNoteType)).ToElements();

                foreach (Element item in textType)
                {
                    item.get_Parameter(BuiltInParameter.TEXT_FONT).Set(choiceFont);
                }

                StyleTextMethod(styles, textType);

                tran.Commit();
            }
        }
        public void TextElementTypeMethod(StyleTextDictionary[] styles, Document doc, string choiceFont)
        {
            using (Transaction tran = new Transaction(doc, "Changing TextElementType"))
            {
                tran.Start();

                ICollection<Element> textElementType =
                    new FilteredElementCollector(doc).OfClass(typeof(TextElementType)).ToElements();

                foreach (Element item in textElementType)
                {
                    item.get_Parameter(BuiltInParameter.TEXT_FONT).Set(choiceFont);
                }

                StyleTextMethod(styles, textElementType);

                tran.Commit();
            }
        }
        public void DimensionTypeMethod(StyleTextDictionary[] styles, Document doc, string choiceFont)
        {
            using (Transaction tran = new Transaction(doc, "Changing TextElementType"))
            {
                tran.Start();

                ICollection<Element> textElementType =
                    new FilteredElementCollector(doc).OfClass(typeof(DimensionType)).ToElements();

                foreach (Element item in textElementType)
                {
                    item.get_Parameter(BuiltInParameter.TEXT_FONT).Set(choiceFont);
                }

                StyleTextMethod(styles, textElementType);

                tran.Commit();
            }
        }
        public void ChangingFamilyMethod(StyleTextDictionary[] styles, Document doc, string choiceFont)
        {
            ICollection<Element> families =
                new FilteredElementCollector(doc).OfClass(typeof(FamilySymbol)).WhereElementIsElementType().ToElements();

            List<string> filteredElements = new List<string>();

            foreach (Element e in families)
            {
                if (e.Category.CategoryType.ToString() == "Annotation")
                {
                    ElementType ele = e as ElementType;
                    string familyName = ele.FamilyName;
                    if (!filteredElements.Contains(familyName))
                    {
                        filteredElements.Add(familyName);

                        FamilySymbol fs = e as FamilySymbol;
                        Family f = fs.Family;
                        Document editFamily = doc.EditFamily(f);
                        doc.EditFamily((e as FamilySymbol).Family);

                        ICollection<Element> elementTextType = new FilteredElementCollector(editFamily).OfClass(typeof(TextNoteType)).ToElements();
                        if (elementTextType.Count > 0) ChangingFamilyMethod(styles, editFamily, choiceFont);

                        TextNoteMethod(styles, editFamily, choiceFont);
                        TextElementTypeMethod(styles, editFamily, choiceFont);
                        editFamily.LoadFamily(doc, new FamilyOptions());
                    }
                }
            }
        }

        public void StyleTextMethod(StyleTextDictionary[] styles, ICollection<Element> elements)
        {
            foreach (StyleTextDictionary style in styles)
            {
                foreach (Element e in elements)
                {
                    if(style.IsStyleUsed == true) e.get_Parameter(style.BuiltInParameterEnum).Set(1);
                    else e.get_Parameter(style.BuiltInParameterEnum).Set(0);
                }
            }
        }
        public class FamilyOptions : IFamilyLoadOptions 
        {
            public bool OnFamilyFound(bool familyInUse, out bool overwriteParameterValues)
            {
                overwriteParameterValues = true;
                return true;
            }

            public bool OnSharedFamilyFound(Family sharedFamily, bool familyInUse, out FamilySource source,
                out bool overwriteParameterValues)
            {
                source = FamilySource.Family;
                overwriteParameterValues = true;
                return true;
            }
        }
    }
}

FontChangingCommandWPF.xaml

<Window x:Class="EEPRevitPlagin.EEPRPCommandModules.FontChanging.LanguageChangeCommandWPF"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:EEPRevitPlagin.EEPRPCommandModules.FontChanging"
             xmlns:re="clr-namespace:EEPRevitPlagin.SecondaryCommand.LangResources"
             mc:Ignorable="d" 
             Title="{x:Static re:Language.Font_Change}"
             WindowStyle="ToolWindow" WindowStartupLocation="CenterScreen" FontFamily="Times New Roman" Width="335" Height="135" ResizeMode="NoResize" SizeToContent="WidthAndHeight">
    <Grid VerticalAlignment="Top">
        <Grid.RowDefinitions>
            <RowDefinition Height="30"/>
            <RowDefinition Height="90"/>
        </Grid.RowDefinitions>
        <Label Content="Choose a font" HorizontalAlignment="Left" Margin="10,0,0,0" Width="220" Height="28" VerticalAlignment="Center"/>
        <Button x:Name="doButton" Content="Apply" Margin="253,0,10,0" Click="Button_Click" FontFamily="Times New Roman" Height="20" VerticalAlignment="Top" Grid.Row="1" Width="70"/>
        <ComboBox x:Name="comboBoxFonts" Margin="10,4,170,0" VerticalAlignment="Top" FontFamily="Times New Roman" Grid.Row="1" Width="155" Height="20"/>
        <CheckBox x:Name="Bold" Content="Bold font" HorizontalAlignment="Left" Margin="10,29,0,0" Grid.Row="1" VerticalAlignment="Top" IsChecked="False"/>
        <CheckBox x:Name="Italic" Content="Italic font" HorizontalAlignment="Left" Margin="10,49,0,26" Grid.Row="1" Checked="Italic_Checked"/>
        <CheckBox x:Name="Underline" Content="Underline font" HorizontalAlignment="Left" Margin="10,69,0,6" Grid.Row="1" RenderTransformOrigin="0.486,-0.593"/>
    </Grid>
</Window>

FontChangingCommandWPF.xaml.cs

using Autodesk.Revit.DB;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Text;
using System.Windows;
using System.Windows.Controls;

namespace EEPRevitPlagin.EEPRPCommandModules.FontChanging
{
    /// <summary>
    /// Interaction logic for FontChangingCommandWPF.xaml
    /// </summary>
    public partial class LanguageChangeCommandWPF : Window
    {
        private Document Doc;
        public LanguageChangeCommandWPF(Document doc)
        {
            InitializeComponent();
            Doc = doc;
 
            InstalledFontCollection installedFontCollection = new InstalledFontCollection();
            FontFamily[] fontFamilies = installedFontCollection.Families;

            int count = fontFamilies.Length;
            for (int i = 0; i < count; ++i)
            {
                comboBoxFonts.Items.Add(fontFamilies[i].Name);
            }
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            string choiceFont = comboBoxFonts.SelectedItem.ToString();

            StyleTextDictionary boldStyle =
                new StyleTextDictionary("boldStyle", Bold.IsChecked, BuiltInParameter.TEXT_STYLE_BOLD);

            StyleTextDictionary italicStyle =
                new StyleTextDictionary("italicStyle", Italic.IsChecked, BuiltInParameter.TEXT_STYLE_ITALIC);

            StyleTextDictionary underlineStyle = 
                new StyleTextDictionary("underlineStyle", Underline.IsChecked, BuiltInParameter.TEXT_STYLE_UNDERLINE);

            StyleTextDictionary[] styles = { boldStyle, italicStyle, underlineStyle };

            FontChangingCommand textNote = new FontChangingCommand();
            textNote.TextNoteMethod(styles, Doc, choiceFont);
            FontChangingCommand textElement = new FontChangingCommand();
            textElement.TextElementTypeMethod(styles, Doc, choiceFont);
            FontChangingCommand dimension = new FontChangingCommand();
            dimension.DimensionTypeMethod(styles, Doc, choiceFont);
            FontChangingCommand changingFamily = new FontChangingCommand();
            changingFamily.ChangingFamilyMethod(styles, Doc, choiceFont);
            MessageBox.Show("Operation completed");
        }

        private void Italic_Checked(object sender, RoutedEventArgs e)
        {

        }
    }

    public class StyleTextDictionary
    {
        public string NameOfStyle { get; set; }
        public bool? IsStyleUsed { get; set; }
        public BuiltInParameter BuiltInParameterEnum { get; set; }
  
        public StyleTextDictionary(string nameOfStyle, bool? isStyleUsed, BuiltInParameter builtInParameterEnum)
        {
            NameOfStyle = nameOfStyle;
            IsStyleUsed = isStyleUsed;
            BuiltInParameterEnum = builtInParameterEnum;
        }
    }
}