ASP.Net: Get Column values in each row while looping using C# and VB.Net

Hi ramco1917,

Please refer below sample.

HTML

<asp:GridView ID="gvDetails" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField HeaderText="Name" DataField="Name" />
        <asp:TemplateField HeaderText="Country">
            <ItemTemplate>
                <asp:Label Text='<%#Eval("Country") %>' runat="server" />
                <asp:HiddenField ID="hfId" runat="server" Value='<%#Eval("CustomerId") %>' />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
<br />
<asp:Button Text="Save" runat="server" OnClick="Save" />
<hr />
<asp:GridView runat="server" ID="gvIds"></asp:GridView>

Namespace

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[3] {
                            new DataColumn("CustomerId", typeof(int)),
                            new DataColumn("Name", typeof(string)),
                            new DataColumn("Country", typeof(string))});
        dt.Rows.Add("01", "John Hammond", "United States");
        dt.Rows.Add("02", "Mudassar Khan", "India");
        dt.Rows.Add("03", "Suzanne Mathews", "France");
        dt.Rows.Add("04", "Robert Schidner", "Russia");
        gvDetails.DataSource = dt;
        gvDetails.DataBind();
    }
}

protected void Save(object sender, EventArgs e)
{
    List<string> ids = new List<string>();
    foreach (GridViewRow row in gvDetails.Rows)
    {
        ids.Add((row.FindControl("hfId") as HiddenField).Value);
    }
    gvIds.DataSource = ids;
    gvIds.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(2) {
                            New DataColumn("CustomerId", GetType(Integer)),
                            New DataColumn("Name", GetType(String)),
                            New DataColumn("Country", GetType(String))})
        dt.Rows.Add("01", "John Hammond", "United States")
        dt.Rows.Add("02", "Mudassar Khan", "India")
        dt.Rows.Add("03", "Suzanne Mathews", "France")
        dt.Rows.Add("04", "Robert Schidner", "Russia")
        gvDetails.DataSource = dt
        gvDetails.DataBind()
    End If
End Sub

Protected Sub Save(ByVal sender As Object, ByVal e As EventArgs)
    Dim ids As List(Of String) = New List(Of String)()
    For Each row As GridViewRow In gvDetails.Rows
        ids.Add((TryCast(row.FindControl("hfId"), HiddenField)).Value)
    Next
    gvIds.DataSource = ids
    gvIds.DataBind()
End Sub

Screenshot