Testing IValueConverter

gistfile1.txt

<Window x:Class="TestIconvert.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:TestIconvert"
        Title="MainWindow" Height="350" Width="525">
    <Window.DataContext>
        <vm:MainWindowViewModel/>
    </Window.DataContext>
    <Window.Resources>
        <vm:CustomConverter x:Key="myConverter"/>
    </Window.Resources>
    <Grid>
        <DataGrid ItemsSource="{Binding ModelAList}" AutoGenerateColumns="False">
            <DataGrid.Columns>
                <DataGridTextColumn Header="ID" Binding="{Binding ID, Mode=TwoWay}"/>
                <DataGridTextColumn Header="Name" Binding="{Binding Name, Mode=TwoWay}"/>
                <DataGridTextColumn Header="Description" Binding="{Binding Description, Mode=TwoWay}"/>
                <DataGridTextColumn Header="ModelBID" Binding="{Binding ModelBID, Mode=TwoWay}"/>
                <DataGridTextColumn Header="ModelB" Binding="{Binding ModelBID, Converter={StaticResource myConverter}}"/>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>

/************************************************************************/

using System;
using System.Collections.Generic;
using System.Windows.Data;

namespace TestIconvert
{
    class CustomConverter : IValueConverter
    {
        public Dictionary<long, ModelB> ModelBDict 
        { 
            get
            {
                // Load from database or whatever here:
                Dictionary<long, ModelB> result = new Dictionary<long, ModelB>();
                result.Add(1200, new ModelB() { Description = "modelB desc", ID = 50, Name = "MB name" });

                return result;
            }
            
        }

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            long i = (long)value;
            try
            {
                ModelB mb = ModelBDict[i];
                return mb.Name;
            }
            catch (Exception)
            {
                return "Not Found in database!";
            }
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

/************************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections.ObjectModel;

namespace TestIconvert
{
    public class MainWindowViewModel : InpcBase // InpcBase is the implementation of INotifyPropertyChanged
    {
        public MainWindowViewModel()
        {
            ModelA m = new ModelA() { Description = "desc", ID = 100, ModelBID = 1200, Name = "MA Name" };
            ModelAList = new ObservableCollection<ModelA>();
            ModelAList.Add(m);

            ModelA m2 = new ModelA() { Description = "desc2", ID = 200, ModelBID = 1500, Name = "MA2 Name" };
            ModelAList.Add(m2);
        }
        public ObservableCollection<ModelA> ModelAList { get; set; }
    }
}

/************************************************************************/

namespace TestIconvert
{
    public class ModelA : InpcBase
    {
        public long ID { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public long ModelBID { get; set; }
    }
}

/************************************************************************/

namespace TestIconvert
{
    public class ModelB
    {
        public long ID { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
    }
}