Maintain DropDownList selected value after Insert using C# and VB.Net in ASP.Net

Hi democloud,

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

HTML

<label>Type:</label>
<asp:DropDownList ID="DropDownList1" class="form-control" runat="server">
    <asp:ListItem Value="0" Text="---Select Type---"></asp:ListItem>
    <asp:ListItem Value="Blank" Text="Blank"></asp:ListItem>
    <asp:ListItem Value="Test1" Text="Test1"></asp:ListItem>
    <asp:ListItem Value="Test2" Text="Test2"></asp:ListItem>
</asp:DropDownList>
<br /><br />
<asp:Button Text="Submit" runat="server" ID="btnSubmit" OnClick="OnSubmit" />

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void OnSubmit(object sender, EventArgs e)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conString"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("INSERT INTO Items VALUES(@Item)", con))
        {
            cmd.CommandType = CommandType.Text;
            string item = "";
            if (DropDownList1.SelectedValue == "Blank")
            {
                item = "\"\"";
            }
            else
            {
                item = DropDownList1.SelectedValue;
            }
            cmd.Parameters.AddWithValue("@Item", item);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
}

VB.Net

Protected Sub OnSubmit(ByVal sender As Object, ByVal e As EventArgs)
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("conString").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("INSERT INTO Items VALUES(@Item)", con)
            cmd.CommandType = CommandType.Text
            Dim item As String = ""
            If DropDownList1.SelectedValue = "Blank" Then
                item = """"""
            Else
                item = DropDownList1.SelectedValue
            End If
            cmd.Parameters.AddWithValue("@Item", item)
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
        End Using
    End Using
End Sub