Update ASP.Net Repeater item based on form data on Button click using C# and VB.Net

Hi JennyD6856,

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

HTML

<div>
    <table class="table table-striped table-bordered table-condensed">
        <tr>
            <td>
                <asp:Panel ID="Panel1" runat="server" ScrollBars="Vertical">
                    <asp:Repeater ID="Repeater1" runat="server">
                        <ItemTemplate>
                            <table class="table table-striped table-bordered table-condensed">
                                <tr>
                                    <td>
                                        Service Name:
                                    </td>
                                    <td>
                                        <asp:Label ID="lblservicename" CssClass="viewlabel" runat="server" Text='<%# Eval("ServiceName") %>'></asp:Label>
                                    </td>
                                    <td rowspan="5">
                                        <asp:Button ID="btnServe" runat="server" Text="Serve" OnClick="btnServe_Click" />
                                    </td>
                                </tr>
                                <tr>
                                    <td>
                                        Service Date:
                                    </td>
                                    <td>
                                        <asp:Label ID="lblservicedate" CssClass="viewlabel" runat="server" Text='<%# Eval("StartDate") %>'></asp:Label>
                                    </td>
                                </tr>
                                <tr>
                                    <td>
                                        Status:
                                    </td>
                                    <td>
                                        <asp:Label ID="lblStatus" CssClass="viewlabel" runat="server" Text="Pending"></asp:Label>
                                    </td>
                                </tr>
                                <tr>
                                    <td>
                                        Technician:
                                    </td>
                                    <td>
                                        <asp:Label ID="lblTechnician" CssClass="viewlabel" runat="server"></asp:Label>
                                    </td>
                                </tr>
                                <tr>
                                    <td>
                                        Comment:
                                    </td>
                                    <td>
                                        <asp:Label ID="lblComment" CssClass="viewlabel" runat="server"></asp:Label>
                                    </td>
                                </tr>
                            </table>
                        </ItemTemplate>
                    </asp:Repeater>
                </asp:Panel>
            </td>
            <td>
                <asp:Panel ID="Panel2" runat="server">
                    <table>
                        <tr>
                            <td>
                                Technician:
                            </td>
                            <td>
                                <asp:DropDownList ID="ddltech" runat="server">
                                    <asp:ListItem Text="Select" Value="Select" />
                                    <asp:ListItem Text="Technician 1" Value="Technician 1" />
                                    <asp:ListItem Text="Technician 2" Value="Technician 2" />
                                    <asp:ListItem Text="Technician 3" Value="Technician 3" />
                                </asp:DropDownList>
                            </td>
                        </tr>
                        <tr>
                            <td>
                                Comment:
                            </td>
                            <td>
                                <asp:TextBox ID="txtcomment" runat="server"></asp:TextBox>
                            </td>
                        </tr>
                        <tr>
                            <td colspan="2">
                                <asp:Button ID="bok" runat="server" Text="Ok" OnClick="bok_Click" />
                            </td>
                        </tr>
                    </table>
                </asp:Panel>
            </td>
        </tr>
    </table>
</div>

Code

C#

static int index = 0;
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        System.Data.DataTable dt = new System.Data.DataTable();
        dt.Columns.AddRange(new System.Data.DataColumn[3] { 
                        new System.Data.DataColumn("Id", typeof(int)),
                        new System.Data.DataColumn("ServiceName", typeof(string)),
                        new System.Data.DataColumn("StartDate",typeof(DateTime)) });
        dt.Rows.Add(1, "Service Name 1", "05/01/2018");
        dt.Rows.Add(2, "Service Name 2", "05/02/2018");
        dt.Rows.Add(3, "Service Name 3", "05/03/2018");
        dt.Rows.Add(4, "Service Name 4", "05/04/2018");
        Repeater1.DataSource = dt;
        Repeater1.DataBind();
    }
}
protected void bok_Click(object sender, EventArgs e)
{
    string technician = ddltech.SelectedValue.ToString();
    string comment = txtcomment.Text;
    (Repeater1.Items[index].FindControl("lblTechnician") as Label).Text = technician;
    (Repeater1.Items[index].FindControl("lblComment") as Label).Text = comment;
}
protected void btnServe_Click(object sender, EventArgs e)
{
    Panel2.Visible = true;
    RepeaterItem item = (sender as Button).NamingContainer as RepeaterItem;
    index = item.ItemIndex;
}

VB.Net

Shared index As Integer = 0
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As System.Data.DataTable = New System.Data.DataTable()
        dt.Columns.AddRange(New System.Data.DataColumn(2) {New System.Data.DataColumn("Id", GetType(Integer)), New System.Data.DataColumn("ServiceName", GetType(String)), New System.Data.DataColumn("StartDate", GetType(DateTime))})
        dt.Rows.Add(1, "Service Name 1", "05/01/2018")
        dt.Rows.Add(2, "Service Name 2", "05/02/2018")
        dt.Rows.Add(3, "Service Name 3", "05/03/2018")
        dt.Rows.Add(4, "Service Name 4", "05/04/2018")
        Repeater1.DataSource = dt
        Repeater1.DataBind()
    End If
End Sub

Protected Sub bok_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim technician As String = ddltech.SelectedValue.ToString()
    Dim comment As String = txtcomment.Text
    CType(Repeater1.Items(index).FindControl("lblTechnician"), Label).Text = technician
    CType(Repeater1.Items(index).FindControl("lblComment"), Label).Text = comment
End Sub

Protected Sub btnServe_Click(ByVal sender As Object, ByVal e As EventArgs)
    Panel2.Visible = True
    Dim item As RepeaterItem = TryCast((TryCast(sender, Button)).NamingContainer, RepeaterItem)
    index = item.ItemIndex
End Sub

Screenshot