Set default value of DropDownList inside of Repeater using C# and VB.Net in ASP.Net

Rameez says:

drpfs.Items.FindByValue(13).Selected = True

FindByValue accepts parameter of string type.

Refer the below sample.

I have the databse table for binding the repeater and dropdownlist like below.

HTML

<asp:Repeater ID="rptCustomers" runat="server" OnItemDataBound="ItemDataBound">
    <HeaderTemplate>
        <table>
            <tr>
                <th>
                    Customer Id
                </th>
                <th>
                    Customer Name
                </th>
                <th>
                    Country
                </th>
            </tr>
    </HeaderTemplate>
    <ItemTemplate>
        <tr>
            <td>
                <asp:Label ID="lblCustomerId" runat="server" Text='<%# Eval("CustomerId") %>' />
            </td>
            <td>
                <asp:Label ID="lblContactName" runat="server" Text='<%# Eval("Name") %>' />
            </td>
            <td>
                <asp:DropDownList runat="server" ID="ddlCountry">
                </asp:DropDownList>
            </td>
        </tr>
    </ItemTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
</asp:Repeater>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindRepeater();
    }
}

private void BindRepeater()
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT TOP 5 * FROM Customers", con))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                cmd.CommandType = CommandType.Text;
                DataTable dt = new DataTable();
                sda.Fill(dt);
                rptCustomers.DataSource = dt;
                rptCustomers.DataBind();
            }
        }
    }
}

private void PopulateDropDownList(DropDownList ddl, string dataTextField, string dataValueField, string query)
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            {
                con.Open();
                DataSet ds = new DataSet();
                da.Fill(ds);
                ddl.DataTextField = dataTextField;
                ddl.DataValueField = dataValueField;
                ddl.DataSource = ds;
                ddl.DataBind();
                ddl.Items.Insert(0, new System.Web.UI.WebControls.ListItem("Please Select", "0"));
            }
        }
    }
}

protected void ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        DropDownList country = e.Item.FindControl("ddlCountry") as DropDownList;
        PopulateDropDownList(country, "CountryName", "CountryID", "SELECT CountryID,CountryName FROM Country");
        country.Items.Insert(0, new ListItem("----Select Location----", "0"));
        country.Items.FindByValue("5").Selected = true;
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindRepeater()
    End If
End Sub

Private Sub BindRepeater()
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand("SELECT TOP 5 * FROM Customers", con)
            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                cmd.CommandType = CommandType.Text
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                rptCustomers.DataSource = dt
                rptCustomers.DataBind()
            End Using
        End Using
    End Using
End Sub

Private Sub PopulateDropDownList(ByVal ddl As DropDownList, ByVal dataTextField As String, ByVal dataValueField As String, ByVal query As String)
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(query, con)
            Using da As SqlDataAdapter = New SqlDataAdapter(cmd)
                con.Open()
                Dim ds As DataSet = New DataSet()
                da.Fill(ds)
                ddl.DataTextField = dataTextField
                ddl.DataValueField = dataValueField
                ddl.DataSource = ds
                ddl.DataBind()
                ddl.Items.Insert(0, New System.Web.UI.WebControls.ListItem("Please Select", "0"))
            End Using
        End Using
    End Using
End Sub

Protected Sub ItemDataBound(ByVal sender As Object, ByVal e As RepeaterItemEventArgs)
    If e.Item.ItemType = ListItemType.Item OrElse e.Item.ItemType = ListItemType.AlternatingItem Then
        Dim country As DropDownList = TryCast(e.Item.FindControl("ddlCountry"), DropDownList)
        PopulateDropDownList(country, "CountryName", "CountryID", "SELECT CountryID,CountryName FROM Country")
        country.Items.Insert(0, New ListItem("----Select Location----", "0"))
        country.Items.FindByValue("5").Selected = True
    End If
End Sub

Output