it works, but still have tiny issues

DicomGrep/MainWindow.xaml

@@ -76,7 +76,7 @@
                             </Grid.ColumnDefinitions>
                             <ComboBox IsEditable="True" ItemsSource="{Binding DicomTagHistory}" Text="{Binding Tag}">
                             </ComboBox>
-                            <Button Content="..." MinWidth="20" Grid.Column="1" Command="{Binding DicomTagLookupCommand}"></Button>
+                            <Button Content="..." MinWidth="20" Grid.Column="1" Command="{Binding DicomDictionaryLookupCommand}"></Button>
                         </Grid>
                         <Label Content="Dicom Tag Value"></Label>
                         <ComboBox IsEditable="True" ItemsSource="{Binding SearchTextHistory}" Text="{Binding SearchText}">

DicomGrep/Services/DicomDictionaryLookupService.cs

@@ -0,0 +1,31 @@
+using DicomGrep.ViewModels;
+using DicomGrep.Views;
+using FellowOakDicom;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DicomGrep.Services
+{
+    public class DicomDictionaryLookupService
+    {
+        public bool SelectDicomDictionaryEntry(ref string dicomTagString)
+        {
+            DicomDictionaryLookupView window = new DicomDictionaryLookupView();
+            DicomDictionaryLookupViewModel vm = window.DataContext as DicomDictionaryLookupViewModel;
+            if (!string.IsNullOrWhiteSpace(dicomTagString))
+            {
+                //build pass
+                //vm.SelectedEntry = DicomTag.Parse(dicomTagString);
+            }
+            if (window.ShowDialog() == true)
+            {
+                dicomTagString = vm.SelectedEntry?.ToString();
+                return true;
+            }
+            return false;
+        }
+    }
+}

DicomGrep/ViewModels/DicomDictionaryLookupViewModel.cs

@@ -0,0 +1,66 @@
+using FellowOakDicom;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DicomGrep.ViewModels
+{
+    public class DicomDictionaryLookupViewModel : ViewModelBase
+    {
+        public ObservableCollection<DicomDictionaryEntry> DicomDictionaryEntries { get; private set; }
+
+        private DicomDictionaryEntry _selectedEntry;
+        public DicomDictionaryEntry SelectedEntry
+        {
+            get { return _selectedEntry; }
+            set { SetProperty(ref _selectedEntry, value); }
+        }
+
+        public DicomDictionaryLookupViewModel() : base()
+        {
+            if (DicomDictionaryEntries == null || DicomDictionaryEntries.Count == 0)
+            {
+                DicomDictionaryEntries = new ObservableCollection<DicomDictionaryEntry>(
+                    GetAllDicomTagDefs().OrderBy(entry=>entry.Tag.Group).ThenBy(entry=>entry.Tag.Element)
+                    .Concat(GetAllPrivateTagDefs()).OrderBy(entry=>entry.Tag.PrivateCreator).ThenBy(entry => entry.Tag.Group).ThenBy(entry => entry.Tag.Element)
+                    );
+            }
+        }
+
+        /// <summary>
+        /// Get all public DICOM tag definitions. Private tags are not included.
+        /// </summary>
+        /// <returns></returns>
+        private IEnumerable<DicomDictionaryEntry> GetAllDicomTagDefs()
+        {
+            return DicomDictionary.Default;
+        }
+
+        /// <summary>
+        /// Get all private DICOM tag definitions.
+        /// </summary>
+        /// <returns></returns>
+        private IEnumerable<DicomDictionaryEntry> GetAllPrivateTagDefs()
+        {
+            ConcurrentDictionary<string, DicomDictionary> _private = typeof(DicomDictionary)
+                .GetField("_private", BindingFlags.NonPublic | BindingFlags.Instance)?
+                .GetValue(DicomDictionary.Default)
+                as ConcurrentDictionary<string, DicomDictionary>;
+
+            // each vendor (private tag creator) can own multiple entries (tags)
+            IEnumerable<DicomDictionary> vendorsDictionary = _private.Select(item => item.Value);
+            foreach (var dictionary in vendorsDictionary) 
+            {
+                foreach( var entry in dictionary)
+                {
+                    yield return entry;
+                }
+            }
+        }
+    }
+}

DicomGrep/ViewModels/MainViewModel.cs

@@ -26,7 +26,7 @@ public class MainViewModel : ViewModelBase
         private readonly ConfigurationService configurationService = new ConfigurationService();
         private readonly FileOperationService fileOperationService = new FileOperationService();
         private readonly SopClassLookupService sopClassLookupService = new SopClassLookupService();
-        private readonly DicomTagLookupService dicomTagLookupService = new DicomTagLookupService();
+        private readonly DicomDictionaryLookupService dicomDictionaryLookupService = new DicomDictionaryLookupService();
         private readonly DialogService dialogService = new DialogService();
         private readonly ExportService exportService = new ExportService();
         private readonly TagValueDetailService tagValueDetailService = new TagValueDetailService();
@@ -226,12 +226,12 @@ public ICommand SopClassLookupCommand
             }
         }
 
-        private ICommand _dicomtagLookupCommand;
-        public ICommand DicomTagLookupCommand
+        private ICommand _dicomDictionaryLookupCommand;
+        public ICommand DicomDictionaryLookupCommand
         {
             get
             {
-                return _dicomtagLookupCommand ?? (_dicomtagLookupCommand = new RelayCommand<object>(_=> DoDicomTagLookup()));
+                return _dicomDictionaryLookupCommand ?? (_dicomDictionaryLookupCommand = new RelayCommand<object>(_=> DoDicomDictionaryLookup()));
             }
         }
 
@@ -447,10 +447,10 @@ private void DoSopClassLookup()
             }
         }
 
-        private void DoDicomTagLookup()
+        private void DoDicomDictionaryLookup()
         {
             string tag = Tag;
-            if (dicomTagLookupService.SelectDicomTag(ref tag))
+            if (dicomDictionaryLookupService.SelectDicomDictionaryEntry(ref tag))
             {
                 Tag = tag;
             }

DicomGrep/Views/DicomTagLookupView.xaml → DicomGrep/Views/DicomDictionaryLookupView.xaml

@@ -1,15 +1,18 @@
-<Window x:Class="DicomGrep.Views.DicomTagLookupView"
+<Window x:Class="DicomGrep.Views.DicomDictionaryLookupView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:DicomGrep.Views"
         xmlns:vm="clr-namespace:DicomGrep.ViewModels"
         mc:Ignorable="d"
-        Title="Looking for DICOM Tag" Height="450" Width="800">
+        Title="Looking for DICOM Tag Dictionary" Height="450" Width="800">
     <Window.DataContext>
-        <vm:DicomTagLookupViewModel/>
+        <vm:DicomDictionaryLookupViewModel/>
     </Window.DataContext>
+    <Window.Resources>
+        <local:TagValueConverter x:Key="TagValueConverter"/>
+    </Window.Resources>
     <Grid>
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto" MinHeight="20"/>
@@ -26,21 +29,22 @@
                 <RowDefinition/>
             </Grid.RowDefinitions>
             <Label Content="Selected:" Grid.Row="0" Grid.Column="0"/>
-            <TextBox Name="selected" Text="{Binding SelectedTag, Mode=OneWay}" Grid.Row="0" Grid.Column="1"/>
+            <TextBox Name="selected" Text="{Binding Path=SelectedEntry, Mode=OneWay, Converter={StaticResource TagValueConverter}, ConverterParameter='X'}" Grid.Row="0" Grid.Column="1"/>
             <Label Content="Filter:" Grid.Row="1" Grid.Column="0"/>
             <TextBox Name="filter" TextChanged="Filter_TextChanged" Grid.Row="1" Grid.Column="1"/>
             <Button Name="pick" Content="Pick" Grid.Column="2" Grid.RowSpan="2" IsDefault="True" Click="pick_Click" Margin="8"/>
         </Grid>
-        <DataGrid Name="dataGridUid" ItemsSource="{Binding DicomTags, Mode=OneWay}"  AutoGenerateColumns="False"
-                  SelectedItem="{Binding SelectedTag, Mode=OneWayToSource}" SelectionMode="Single"
+        <DataGrid Name="dataGridUid" ItemsSource="{Binding DicomDictionaryEntries, Mode=OneWay}"  AutoGenerateColumns="False"
+                  SelectedItem="{Binding SelectedEntry, Mode=OneWayToSource}" SelectionMode="Single"
                   Grid.Row="1" MouseDoubleClick="dataGridUid_MouseDoubleClick">
             <DataGrid.Columns>
-                <DataGridTextColumn Header="Tag" Binding="{Binding .,Mode=OneWay}"/>
-                <DataGridTextColumn Header="Name" Binding="{Binding DictionaryEntry.Name,Mode=OneWay}"/>
-                <DataGridTextColumn Header="Group" Binding="{Binding Group,Mode=OneWay}"/>
-                <DataGridTextColumn Header="Element" Binding="{Binding Element,Mode=OneWay}"/>
-                <DataGridCheckBoxColumn Header="IsPrivate" Binding="{Binding IsPrivate,Mode=OneWay}"/>
-                <DataGridTextColumn Header="Private Creator" Binding="{Binding PrivateCreator, Mode=OneWay}"/>
+                <DataGridTextColumn Header="Tag" Binding="{Binding Tag,Mode=OneWay, Converter={StaticResource TagValueConverter}, ConverterParameter='C'}"/>
+                <DataGridTextColumn Header="Name" Binding="{Binding Name,Mode=OneWay}"/>
+                <DataGridTextColumn Header="Group" Binding="{Binding Tag.Group,Mode=OneWay}"/>
+                <DataGridTextColumn Header="Element" Binding="{Binding Tag.Element,Mode=OneWay}"/>
+                <DataGridCheckBoxColumn Header="IsRetired" Binding="{Binding IsRetired,Mode=OneWay}"/>
+                <DataGridCheckBoxColumn Header="IsPrivate" Binding="{Binding Tag.IsPrivate,Mode=OneWay}"/>
+                <DataGridTextColumn Header="Private Creator" Binding="{Binding Tag.PrivateCreator, Mode=OneWay}"/>
             </DataGrid.Columns>
         </DataGrid>
 

DicomGrep/Views/DicomTagLookupView.xaml.cs → DicomGrep/Views/DicomDictionaryLookupView.xaml.cs

@@ -17,11 +17,11 @@
 namespace DicomGrep.Views
 {
     /// <summary>
-    /// Interaction logic for DicomTagLookupView.xaml
+    /// Interaction logic for DicomDictionaryLookupView.xaml
     /// </summary>
-    public partial class DicomTagLookupView : Window
+    public partial class DicomDictionaryLookupView : Window
     {
-        public DicomTagLookupView()
+        public DicomDictionaryLookupView()
         {
             InitializeComponent();
         }
@@ -36,10 +36,10 @@ private void Filter_TextChanged(object sender, TextChangedEventArgs e)
             {
                 cv.Filter = obj =>
                 {
-                    DicomTag tag = obj as DicomTag;
-                    return tag.ToString().Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase) ||
-                    tag.DictionaryEntry.Keyword.Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase) ||
-                    tag.DictionaryEntry.Name.Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase);
+                    DicomDictionaryEntry dictionary = obj as DicomDictionaryEntry;
+                    return dictionary.ToString().Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase) ||
+                    dictionary.Keyword.Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase) ||
+                    dictionary.Name.Contains(filterText.Trim(), StringComparison.OrdinalIgnoreCase);
 
                 };
             }

DicomGrep/Views/TagValueConverter.cs

@@ -0,0 +1,49 @@
+using FellowOakDicom;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Data;
+
+namespace DicomGrep.Views
+{
+    [ValueConversion(typeof(DicomTag), typeof(string))]
+    public class TagValueConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (value is DicomTag dicomTag)
+            {
+                string para = "X";
+                if (parameter is string _p && !string.IsNullOrWhiteSpace(_p))
+                {
+                    para = (string)parameter;
+                }
+
+                if (para == "C")
+                {
+                    if (dicomTag.PrivateCreator == null)
+                    {
+                        return $"({dicomTag.Group:x4},{dicomTag.Element:x4})";
+                    }
+                    return $"({dicomTag.Group:x4},xx{dicomTag.Element & 0xFF:x2})";
+                }
+                else
+                {
+                    return dicomTag.ToString(para, null);
+                }
+            }
+            else
+            {
+                return value;
+            }
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}