ASP.Net: Merge DataTable row items into one with comma separated value using C# and VB.Net

Hi satabeach,

Refer below sample.

HTML

<asp:GridView ID="gvCustomer" runat="server">
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] { new DataColumn("ID")});
        dt.Rows.Add("1555");
        dt.Rows.Add("1556");
        dt.Rows.Add("1557");
        var list = dt.AsEnumerable().Select(r => r["ID"].ToString());
        string value = string.Join(",", list);
        dt.Rows.Clear();
        dt.Rows.Add(value);
        gvCustomer.DataSource = dt;
        gvCustomer.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn() {New DataColumn("ID")})
        dt.Rows.Add("1555")
        dt.Rows.Add("1556")
        dt.Rows.Add("1557")
        Dim list = dt.AsEnumerable().[Select](Function(r) r("ID").ToString())
        Dim value As String = String.Join(",", list)
        dt.Rows.Clear()
        dt.Rows.Add(value)
        gvCustomer.DataSource = dt
        gvCustomer.DataBind()
    End If
End Sub

Output

      ID

1555,1556,1557