Delete all records from DataTable having more than one records using C# and VB.Net in ASP.Net

Hi Rockstar8

Check this sample now please take its reference.

HTML

<asp:GridView runat="server" ID="gvDetails" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="ID" HeaderText="ID" />
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;
using System.Linq;

VB.Net

Imports System.Data
Imports System.Linq

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.Page.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("ID");
        dt.Rows.Add("60");
        dt.Rows.Add("30");
        dt.Rows.Add("60");
        dt.Rows.Add("43");
        dt.Rows.Add("60");

        var result = from row in dt.AsEnumerable()
                        group row by row["ID"] into gr
                        select new
                        {
                            Id = gr.FirstOrDefault()["ID"],
                            Count = gr.Count()
                        };
        foreach (var item in result)
        {
            if (item.Count > 1)
            {
                DataRow[] dr = dt.Select("ID = " + item.Id);
                foreach (DataRow row in dr)
                {
                    dt.Rows.Remove(row);
                }
                dt.AcceptChanges();
            }
        }
        this.gvDetails.DataSource = dt;
        this.gvDetails.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.Page.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.Add("ID")
        dt.Rows.Add("60")
        dt.Rows.Add("30")
        dt.Rows.Add("60")
        dt.Rows.Add("43")
        dt.Rows.Add("60")
        Dim result = From row In dt.AsEnumerable()
                     Group row By Key = row("ID") Into Group
                     Select New With {
                      .Id = Group.FirstOrDefault()("ID"),
                      .Count = Group.Count()
                    }
        For Each item In result
            If item.Count > 1 Then
                Dim dr As DataRow() = dt.Select("ID = " & item.Id)
                For Each row As DataRow In dr
                    dt.Rows.Remove(row)
                Next
                dt.AcceptChanges()
            End If
        Next
        Me.gvDetails.DataSource = dt
        Me.gvDetails.DataBind()
    End If
End Sub

Output

ID

30

43