Asp.Net Gridview - One Column is List<string> - Want to Show Only The Last Item

Question

I have an Asp.Net GridView. One of the Columns is a List, but I only want to show the Last Item in the list. How can I do this?

List<string> Column1

I am binding the Gridview to a business object:

public Class GridObject
{
    List<string> Column1 { get; set; }
}

EDIT

This worked, but is it the best solution:

<%# ((List<string>)Eval("Column1"))[((List<string>)Eval("Column1")).Count - 1] %>

Answer 1

Your best bet is to create a template column and use an inline script to retrieve the value from the list:

<%= ((List<string>)DataBinder.Eval("Column1"))[((List<string>)DataBinder.Eval("Column1")).Count] %>

Or you could store the result in the text of a label or a literal.

Hope that helps

Answer 2

I would add a property to the object you are binding to, and use that property instead of the list property in your binding.

public Class GridObject
{
    List<string> Column1 { get; set; }
    public string Column1LastValue
    { 
      get
      {   // return Column1.Last(); if linq is available
          return Column1[Column1.Count-1];
      }
    }
}

Edit: Adding a presentation wrapper allows you to unit test what will be displayed. You are doing a translation in the view, which is OK, but since you technically have some logic happening to translate your business object to something proper for display, you would likely want to unit test that translation. Then, any formatting you want to apply to any of your business object fields is wrapped in a testable class, rather than hidden on the untestable view. Here is a sample of how this could be done:

public class GridObjectView
{
    private GridObject _gridObject;

    public GridObjectView(GridObject gridObject)
    {
        _gridObject = gridObject;
    }

    public string Column1
    {
        get
        {
            return _gridObject.Column1.Last();
        }
    }
}

Then to do the databinding, you could do this:

List<GridObject> data = GetGridData();

grid.DataSource = data.Select(g => new GridObjectView(g));
grid.DataBind();