问题:

I'm using two drop down and bind values to that drop down. Now am adding a new button add_new. I want to create the above drop downs below when I click the add button and maintain the previous selected values. Please help me to do this.

回答1:

You can achieve the desired result using Repeater control of ASP.Net. You can create any type of template as you wish, see the code below:

ASPX:

<asp:Repeater ID="Repeater1" runat="server">
    <ItemTemplate>
        <asp:DropDownList ID="DropDownList1" runat="server" />
        <asp:DropDownList ID="DropDownList2" runat="server" />
        <br />
    </ItemTemplate>
</asp:Repeater>

CodeBehind:

protected void Button1_Click(object sender, EventArgs e)
{
    // data fetching logic

    Repeater1.DataSource = data;
    Repeater1.DataBind();
}

回答2:

Hard to answer without a better explanation and code samples but from experience doing anything with dropdowns over postbacks is better controlled with hidden fields. Set the value of the hidden field with javascript. Please provide more detail.