Question

If my dropdown has a value selected, I want to show the selected item text in my textbox. If not, I want to empty it.

<asp:DropDownList ID="ddl"  runat="server" AutoPostBack="true" onselectedindexchanged="ddlSelectedIndexChanged" Width="200px" onchange="ddlChange()">
</asp:DropDownList>
<asp:TextBox ID="hdntxtbxTaksit" runat="server" Visible="false"></asp:TextBox>

How can I do this?

Answer 1

Using jQuery;

$().ready(function(){           
  $('#<%=ddl.ClientID %>').change(function () {               
    $('#<%=hdntxtbxTaksit.ClientID %>').val($(this).val() == "0" ? "" : $(this).val());              
  });
});

EDIT: With above method, you don’t need to call onchange event of the dropdown. So your markup can be

<asp:DropDownList ID="ddl"  runat="server" AutoPostBack="true"
         onselectedindexchanged="ddlSelectedIndexChanged" Width="200px">
</asp:DropDownList>
<asp:TextBox ID="hdntxtbxTaksit" runat="server" Visible="false"></asp:TextBox>