在jQuery中将dropdownlist值设置为textbox

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

If you want to assign selected value of dropdownlist to text box you can assign in change event without and condition as change event means dropdown have been selected .

With javascript

Change

onchange="ddlChange()"

To

onchange="ddlChange(this)"

Your javascrpt method would be

function ddlChange(ddl)
{      
      document.getElementById('<%= hdntxtbxTaksit.ClientId %>').value = this.value;
}

With jQuery

Remove onchange="ddlChange()" as we will bind event with jquery.

$('<%= ddl.ClientId %>').change(function(){          
          $('<%= hdntxtbxTaksit.ClientId %>').val($(this).val());    
});

Answer 2

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>

Answer 3

you can do it like this

function ddlChange()
{
   if(document.getElementById('<%= ddl.ClientId %>').value=='0')
   {
      document.getElementById('<%= hdntxtbxTaksit.ClientId %>').value = "";
   }
   else
   {
      document.getElementById('<%= hdntxtbxTaksit.ClientId %>').value = document.getElementById('<%= ddl.ClientId %>').value;    
   }
}

Answer 4

Try this code and remove onchange event added in your asp:dropdownlist

Note: AUTOPOSTBACK property will always do a page submit, it wont stop even if you return false in onchange method of dropdown

        $(document).ready(function () {
            $('#<%=ddl.ClientID %>').change(function () {

                if ($(this).val() != "0") {
                    $('#<%= hdntxtbxTaksit.ClientID %>').val($(this).val());
                }
                else {
                    $('#<%= hdntxtbxTaksit.ClientID %>').val("");
                }
            });

        });