How can I create as many of the same databound comboboxes but pull different values from the same fieldname?

Question

I hope this question becomes clearer with the example. Essentially, I have a class of steel angles (and I need to know their widths and thicknesses). I want to load them from a .csv, and create as many as needed for k < count.

The first example:

XAML

            <DataGridTemplateColumn x:Name="cBoxes" Header="Size" Width="*" CanUserReorder="False" CanUserSort="False" CanUserResize="False" IsReadOnly="True">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <ComboBox x:Name="testBox" Margin="2" ItemsSource="{Binding eID}" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>

        </DataGrid.Columns>
    </DataGrid>

Code Behind

    public class Angles
    {
        public double TYPE { get; set; }
        public string eID { get; set; }
        public double WIDTH { get; set; }
        public ObservableCollection<double> THICKNESS { get; set; }
    }

    private ObservableCollection<Angles> angleDb = new ObservableCollection<Angles>();
    private ObservableCollection<string> angleIDStrings = new ObservableCollection<string>();

public void LoadAngles()
    {
        var wn = Convert.ToDouble(textboxWebNumber.Text);
        var twn = wn % 2 == .5 ? wn + (wn / 2 - .5) + 6 : wn + (Math.Floor(wn / 2)) + 6;

        var csvColl = (from line in File.ReadAllLines("angledb.csv").Skip(1)
                       let parts = line.Split(',')
                       select new
                       {
                           Width = Convert.ToDouble(parts[0]),
                           Thickness = Convert.ToDouble(parts[1])
                       }).ToList();
        foreach (var item in csvColl)
        {
            var content = $"L{item.Width}x{item.Width}x{item.Thickness}";
            angleIDStrings.Add(content);
            angleDb.Add(new Angles() { 
THICKNESS = item.Thickness, WIDTH = item.Width, eID = angleIDStrings });
        }

        DataContext = angleDb;
    }

The logic of this essentially loads each angle with all possible angle eIDs, or all possible variations of the angle dimensions. This actually does what I want, with the exception that the datagrid is populated with as many comboboxes as there are eIDs, or eID.Count.

The second example should make clearer what I want:

public class Angles
    {
        public double TYPE { get; set; }
        public ObservableCollection<string> eID { get; set; }
        public ObservableCollection<double> WIDTH { get; set; }
        public ObservableCollection<double> THICKNESS { get; set; }

    } // modify the class, changing all fields to observablecollections

 private ObservableCollection<double> angleWidths = new ObservableCollection<double>();
    private ObservableCollection<double> angleThicknesses = new ObservableCollection<double>();

    public List<Angles> finalList = new List<Angles>();
    public void LoadAngles()
    {
        var wn = Convert.ToDouble(textboxWebNumber.Text);
        var twn = wn % 2 == .5 ? wn + (wn / 2 - .5) + 6 : wn + (Math.Floor(wn / 2)) + 6;
        // Read each line, break it at commas, assign split-elements, save into a list.
        var csvColl = (from line in File.ReadAllLines("angledb.csv").Skip(1)
                       let parts = line.Split(',')
                       select new
                       {
                           Width = Convert.ToDouble(parts[0]),
                           Thickness = Convert.ToDouble(parts[1])
                       }).ToList();
        foreach (var item in csvColl)
        {
            var content = $"L{item.Width}x{item.Width}x{item.Thickness}";
            angleIDStrings.Add(content);
            angleThicknesses.Add(item.Thickness);
            angleWidths.Add(item.Width);
        }

        for (var k = 0; k < twn; k++)
        {

            angleDb.Add(new Angles
            {
                THICKNESS = angleThicknesses,
                WIDTH = angleWidths,
                eID = angleIDStrings
            });
        }
        DataContext = angleDb;
    }

The logic here is essentially setting up one "template" angle, each which have all possible variations, and adding them based on k < twn

This will generate as many comboboxes, but will prove problematic when trying to pull the SelectedValue from them.

How can I find the in-between solution?

Answer 1

Your problem is bad design - u should use MVVM pattern.

But the simple solution is: XAML

            <DataGridTemplateColumn x:Name="cBoxes" Header="Size" Width="*" CanUserReorder="False" CanUserSort="False" CanUserResize="False" IsReadOnly="True">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
<ComboBox x:Name="testBox" Margin="2" SelectedItem="{Binding SelectedEID, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" ItemsSource="{Binding eID}" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>

C#

public class Angles
    {
        public double TYPE { get; set; }
        public string SelectedEID { get; set; }


        public ObservableCollection<string> eID { get; set; }
        public ObservableCollection<double> WIDTH { get; set; }
        public ObservableCollection<double> THICKNESS { get; set; }

    } 

Obviously the Angles class has now a new Property to hold the SelectedItem.

Anyway check out this Link