Display dynamic columns in ASP.Net Repeater using C# and VB.Net

Hi ramco1917,

As this is not possible through Repeater.Therefore we take GridView.

Please refer below sample.

HTML

<asp:GridView runat="server" ID="gvDetails" />
<asp:Button runat="server" Text="Convert" OnClick="Convert" />

Namespace

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt1 = new DataTable();

        dt1.Columns.AddRange(new DataColumn[] { new DataColumn("ID"),
                                                new DataColumn("Name"),
                                                new DataColumn("TrainingDateFrom"),
                                                new DataColumn("TrainingDateTo")});
        dt1.Rows.Add("1", "Dealer", "20/09/2022", "25/09/2022");

        DataTable dt2 = new DataTable();
        dt2.Columns.AddRange(new DataColumn[] { 
            new DataColumn("Aid"),
            new DataColumn("ID"),
            new DataColumn("Date"),
            new DataColumn("Status")});
        dt2.Rows.Add("1", "1", "20/09/2022", "P");
        dt2.Rows.Add("2", "1", "21/09/2022", "P");
        dt2.Rows.Add("3", "1", "22/09/2022", "A");
        dt2.Rows.Add("4", "1", "23/09/2022", "P");

        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] {
            new DataColumn("Name"),
            new DataColumn("Date"),
            new DataColumn("Status")});

        var result = (from table1 in dt1.AsEnumerable()
                        join table2 in dt2.AsEnumerable()
                        on table1["ID"] equals table2["ID"]
                        select new
                        {
                            Name = table1["Name"],
                            Date = table2["Date"],
                            Status = table2["Status"]
                        });

        foreach (var item in result.ToList())
        {
            dt.Rows.Add(item.Name, item.Date, item.Status);
        }

        ViewState["dt"] = dt;
        BindGrid(dt);
    }
}

protected void Convert(object sender, EventArgs e)
{
    DataTable dt = (DataTable)ViewState["dt"];
    DataTable dt2 = new DataTable();
    dt2.Columns.Add(new DataColumn("Id"));
    dt2.Columns.Add("Name");

    List<string> dates = dt.AsEnumerable().Select(x => x["Date"].ToString()).Distinct().ToList();
    for (int i = 0; i < dates.Count; i++)
    {
        dt2.Columns.Add(dates[i]);
    }
    List<string> names = dt.AsEnumerable().Select(x => x["Name"].ToString()).Distinct().ToList();
    for (int i = 0; i < names.Count; i++)
    {
        DataRow dr = dt2.NewRow();
        dr[0] = i + 1;
        dr[1] = names[i];
        for (int j = 0; j < dates.Count; j++)
        {
            DataRow[] row = dt.Select("Name='" + names[i] + "' AND Date='" + dates[j] + "'");
            dr[j + 2] = row.Length > 0 ? row[0]["Status"].ToString() : string.Empty;
        }
        dt2.Rows.Add(dr);
    }

    BindGrid(dt2);
}

private void BindGrid(DataTable dt)
{
    gvDetails.DataSource = dt;
    gvDetails.DataBind();
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt1 As DataTable = New DataTable()
        dt1.Columns.AddRange(New DataColumn() {New DataColumn("ID"), New DataColumn("Name"), New DataColumn("TrainingDateFrom"), New DataColumn("TrainingDateTo")})
        dt1.Rows.Add("1", "Dealer", "20/09/2022", "25/09/2022")
        Dim dt2 As DataTable = New DataTable()
        dt2.Columns.AddRange(New DataColumn() {New DataColumn("Aid"), New DataColumn("ID"), New DataColumn("Date"), New DataColumn("Status")})
        dt2.Rows.Add("1", "1", "20/09/2022", "P")
        dt2.Rows.Add("2", "1", "21/09/2022", "P")
        dt2.Rows.Add("3", "1", "22/09/2022", "A")
        dt2.Rows.Add("4", "1", "23/09/2022", "P")
        Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn() {New DataColumn("Name"), New DataColumn("Date"), New DataColumn("Status")})
        Dim result = (From table1 In dt1.AsEnumerable()
                      Join table2 In dt2.AsEnumerable()
                      On table1("ID") Equals table2("ID")
                      Select New With {
                          .Name = table1("Name"),
                          .Date = table2("Date"),
                          .Status = table2("Status")
                      })
        For Each item In result.ToList()
            dt.Rows.Add(item.Name, item.Date, item.Status)
        Next
        ViewState("dt") = dt
        BindGrid(dt)
    End If
End Sub

Protected Sub Convert(ByVal sender As Object, ByVal e As EventArgs)
    Dim dt As DataTable = CType(ViewState("dt"), DataTable)
    Dim dt2 As DataTable = New DataTable()
    dt2.Columns.Add(New DataColumn("Id"))
    dt2.Columns.Add("Name")
    Dim dates As List(Of String) = dt.AsEnumerable().[Select](Function(x) x("Date").ToString()).Distinct().ToList()
    For i As Integer = 0 To dates.Count - 1
        dt2.Columns.Add(dates(i))
    Next
    Dim names As List(Of String) = dt.AsEnumerable().[Select](Function(x) x("Name").ToString()).Distinct().ToList()
    For i As Integer = 0 To names.Count - 1
        Dim dr As DataRow = dt2.NewRow()
        dr(0) = i + 1
        dr(1) = names(i)
        For j As Integer = 0 To dates.Count - 1
            Dim row As DataRow() = dt.[Select]("Name='" & names(i) & "' AND Date='" + dates(j) & "'")
            dr(j + 2) = If(row.Length > 0, row(0)("Status").ToString(), String.Empty)
        Next
        dt2.Rows.Add(dr)
    Next
    BindGrid(dt2)
End Sub

Private Sub BindGrid(ByVal dt As DataTable)
    gvDetails.DataSource = dt
    gvDetails.DataBind()
End Sub

Screenshot