CODEWITHSUNDEEP
c#asp.netwebforms
joseph Laurello
joseph Laurello

Reputation: 107

Removing Duplicates from a dropdown list

I had some help earlier on another post to remove the file extension in my dropdown list. I now need to remove duplicates. This is the current before and after:

Before:

video-1.mp4
video-1.ogv
video-1.webm

After: (Current code)

video-1
video-1
video-1

What I want:

video-1

Here is my code behind:

  protected void Page_Load(object sender, EventArgs e)
  {
    if (!IsPostBack)
    {
      BindGrid();
    }

    if (!IsPostBack)
    {
      string[] filePaths = Directory.GetFiles(Server.MapPath("~/Uploads/"));
      List<ListItem> files = new List<ListItem>();
      foreach (string filePath in filePaths)
      {
        var item = new ListItem(Path.GetFileNameWithoutExtension(filePath), filePath);
        if (!files.Contains(item))
          files.Add(item);
      }

      DropDownList1.DataSource = files;
      DropDownList1.DataTextField = "";
      DropDownList1.DataValueField = "";
      DropDownList1.DataBind();
    }
  }

Upvotes: 0

Views: 140

Answers (2)

Yacoub Massad
Yacoub Massad

Reputation: 27861

I am assuming that you want to keep the filePath (at least for some of the files) and store it as the value of the ListItem as shown by your code.

You can use a Dictionary like this:

Dictionary<string,string> filenames = new Dictionary<string, string>();

foreach (string filePath in filePaths)
{
    var file_name_without_extension = Path.GetFileNameWithoutExtension(filePath);

    if(filenames.ContainsKey(file_name_without_extension))
        continue;

    filenames.Add(file_name_without_extension, filePath);
}

List<ListItem> files = filenames.Select(x => new ListItem(x.Key, x.Value)).ToList();

Upvotes: 1

Filip
Filip

Reputation: 1864

LINQ's extension method .Distinct() will help. You may need to manually add using System.Linq;

Don't forget that it will return new collection without duplict elements instead of modifying current one.

Upvotes: 1

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