Insert multiple columns in StringBuilder from StringCollection and stored in DataTable using C# and VB.Net in ASP.Net

Hi Amol111,

Check this example. Now please take its reference and correct your code.

HTML

<table>
    <tr>
        <td>
            <asp:GridView ID="grdDetails" runat="server" AutoGenerateColumns="false">
                <Columns>
                    <asp:TemplateField HeaderText="Details">
                        <ItemTemplate>
                            Complete :
                            <asp:CheckBox ID="Chk_Complete" Checked='<%#Eval("Completed") %>' runat="server" />
                            <br />
                            Employee Id :
                            <asp:Label ID="lblEmpl_Id" Text='<%#Eval("EmployeeId") %>' runat="server" />
                            <br />
                            Date :
                            <asp:Label ID="lbl_Initiation_Date" Text='<%#Convert.ToDateTime(Eval("Date")).ToString("dd/MM/yyyy") %>'
                                runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>
        </td>
        <td>
            <asp:Label ID="lblTable" runat="server" />
        </td>
    </tr>
</table>
<br />
<asp:Button Text="Save" runat="server" OnClick="Save" />

Namespaces

C#

using System.Collections.Specialized;
using System.Data;
using System.Text;

VB.Net

Imports System.Collections.Specialized
Imports System.Data
Imports System.Text

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("EmployeeId", typeof(int)),
                        new DataColumn("Date", typeof(DateTime)),
                        new DataColumn("Completed",typeof(bool)) });
        dt.Rows.Add(1, DateTime.Now, false);
        dt.Rows.Add(2, DateTime.Now.AddDays(1), false);
        dt.Rows.Add(3, DateTime.Now.AddDays(5), false);
        dt.Rows.Add(4, DateTime.Now.AddDays(-10), false);
        grdDetails.DataSource = dt;
        grdDetails.DataBind();
    }
}

protected void Save(object sender, EventArgs e)
{
    StringCollection sc = new StringCollection();
    for (int i = 0; i < grdDetails.Rows.Count; i++)
    {
        CheckBox checkbox = (CheckBox)grdDetails.Rows[i].Cells[0].FindControl("Chk_Complete");
        Label lblEmpl_Id = (Label)grdDetails.Rows[i].Cells[0].FindControl("lblEmpl_Id");
        Label lbl_Initiation_Date = (Label)grdDetails.Rows[i].Cells[0].FindControl("lbl_Initiation_Date");

        if (checkbox != null)
        {
            if (checkbox.Checked)
            {
                string EmpId = lblEmpl_Id.Text;
                string Trn_Initiation_Date = lbl_Initiation_Date.Text;
                sc.Add(EmpId);
                sc.Add(Trn_Initiation_Date);
            }
        }
    }

    DataTable dtItem_Completion = new DataTable();
    dtItem_Completion.Columns.Add("ID", typeof(int));
    dtItem_Completion.Columns.Add("EmpId", typeof(int));
    dtItem_Completion.Columns.Add("Trn_Initiation_Date", typeof(string));

    StringBuilder sb = new StringBuilder();
    sb.Append("<table><tr><th>Id</th><th>Employee Id</th><th>Date</th></tr>");
    DataRow dr = null;
    int j = 0;
    for (int i = 0; i < sc.Count / 2; i++)
    {
        sb.Append("<tr>");
        dr = dtItem_Completion.NewRow();
        dr["ID"] = i + 1;
        sb.Append("<td>" + (i + 1) + "</td>");
        dr["EmpId"] = sc[j];
        sb.Append("<td>" + sc[j] + "</td>");
        j++;
        dr["Trn_Initiation_Date"] = sc[j];
        sb.Append("<td>" + sc[j] + "</td>");
        j++;
        dtItem_Completion.Rows.Add(dr);
        sb.Append("</tr>");
    }
    sb.Append("</table>");
    lblTable.Text = sb.ToString();
}

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("EmployeeId", GetType(Integer)),
                            New DataColumn("Date", GetType(DateTime)),
                            New DataColumn("Completed", GetType(Boolean))})
        dt.Rows.Add(1, DateTime.Now, False)
        dt.Rows.Add(2, DateTime.Now.AddDays(1), False)
        dt.Rows.Add(3, DateTime.Now.AddDays(5), False)
        dt.Rows.Add(4, DateTime.Now.AddDays(-10), False)
        grdDetails.DataSource = dt
        grdDetails.DataBind()
    End If
End Sub

Protected Sub Save(ByVal sender As Object, ByVal e As EventArgs)
    Dim sc As StringCollection = New StringCollection()
    For i As Integer = 0 To grdDetails.Rows.Count - 1
        Dim checkbox As CheckBox = CType(grdDetails.Rows(i).Cells(0).FindControl("Chk_Complete"), CheckBox)
        Dim lblEmpl_Id As Label = CType(grdDetails.Rows(i).Cells(0).FindControl("lblEmpl_Id"), Label)
        Dim lbl_Initiation_Date As Label = CType(grdDetails.Rows(i).Cells(0).FindControl("lbl_Initiation_Date"), Label)
        If checkbox IsNot Nothing Then
            If checkbox.Checked Then
                Dim EmpId As String = lblEmpl_Id.Text
                Dim Trn_Initiation_Date As String = lbl_Initiation_Date.Text
                sc.Add(EmpId)
                sc.Add(Trn_Initiation_Date)
            End If
        End If
    Next
    Dim dtItem_Completion As DataTable = New DataTable()
    dtItem_Completion.Columns.Add("ID", GetType(Integer))
    dtItem_Completion.Columns.Add("EmpId", GetType(Integer))
    dtItem_Completion.Columns.Add("Trn_Initiation_Date", GetType(String))
    Dim sb As StringBuilder = New StringBuilder()
    sb.Append("<table><tr><th>Id</th><th>Employee Id</th><th>Date</th></tr>")
    Dim dr As DataRow = Nothing
    Dim j As Integer = 0
    For i As Integer = 0 To sc.Count / 2 - 1
        sb.Append("<tr>")
        dr = dtItem_Completion.NewRow()
        dr("ID") = i + 1
        sb.Append("<td>" & (i + 1) & "</td>")
        dr("EmpId") = sc(j)
        sb.Append("<td>" & sc(j) & "</td>")
        j += 1
        dr("Trn_Initiation_Date") = sc(j)
        sb.Append("<td>" & sc(j) & "</td>")
        j += 1
        dtItem_Completion.Rows.Add(dr)
        sb.Append("</tr>")
    Next
    sb.Append("</table>")
    lblTable.Text = sb.ToString()
End Sub

Screenshot

Note: Since in StringCollection adding 2 columns i have devided the for loop with 2. So change code according to your column.