Question

I have a simple datalist with a dropdownlist and a textbox.

When the dropdownlist selected index changes, I want to load a value into the textbox in that listbox item (i.e., the textbox on that particular row).

<ItemTemplate>
    <asp:DropDownList runat="server" 
        ID="ddlCategory" AutoPostBack="true"
        DataTextField="category"
        DataValueField="category_code" 
        OnSelectedIndexChanged="ddlCategory_SelectedIndexChanged" />                      
    <br />
    Code<asp:TextBox 
        runat="server" 
        ID="txtOutputCode" 
        Text='<%# Bind("output_code") %>' />
</ItemTemplate>

How do I do this?

The challenge I’m facing is how to find the corresponding textbox to update.

E.g. for a button I’d pass a commandname, and command arguments. And then I’d handle the event in the gridview or datalist to find the corresponding textbox and update the text. What can we do in case of a selectedindex change of a dropdownlist?

Answer 1

I guess this should work. Try this…

protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
{
   var ddlList= (DropDownList)sender;
   var row = (GridViewRow)ddlList.NamingContainer;
   //get the Id of the row
   var Id = Convert.ToInt32(((Label)row.FindControl("IdColumn")).Text);
}