CODEWITHSUNDEEP
c#asp.netdrop-down-menu
JJ.
JJ.

Reputation: 9950

How do I disable a dropdownlist item based on a user selection on another drop down in ASP.NET?

I have two drop down lists with a handful of items.

If the user selects X, X needs to be disabled from the next drop down.

If the user selects Y, Y needs to be disabled from the next drop down.

And vice-versa.

I tried this but it is not working:

protected void ddlSearchColumn1_SelectedIndexChanged(object sender, EventArgs e)
{
    var ddl = (DropDownList) sender;

    string itemSelected = ddl.SelectedValue;

    ddlSearchColumn2.Items.FindByValue(itemSelected).Enabled = false;
}

Can anyone give me a hand?

Upvotes: 8

Views: 37464

Answers (5)

hawk
hawk

Reputation: 41

For some reason, this worked for me:

 if (ddlState.SelectedValue == "AK")
    {
        MyDdl.Items.FindByValue("1111111").Enabled = false;

}

Upvotes: 4

JJ.
JJ.

Reputation: 9950

I figured I'd add here.

Two things we forgot to add:

EnableViewState="True" AutoPostBack="True"

If you don't add those to the control, the event is not fired.

Upvotes: 0

user2453734
user2453734

Reputation:

You were very close:

MarkUP:

List 1: <asp:DropDownList ID="ddlSearchColumn1" runat="server" OnSelectedIndexChanged="ddlSearchColumn1_SelectedIndexChanged" AutoPostBack="true" />
List 2: <asp:DropDownList ID="ddlSearchColumn2" runat="server" AutoPostBack="true" />

Code Behind:

public partial class _Default : Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {//JUST PUT SOMETHING IN THE DROPDOWN BOXES
            var items1 = new List<ListItem>()
            {
                new ListItem("Select Option"),
                new ListItem("Test 1"),
                new ListItem("Test 2"),
                new ListItem("Test 3")
            };

            var items2 = new List<ListItem>()
            {
                new ListItem("Select Option", ""),
                new ListItem("DDL 2 Test 1"),
                new ListItem("DDL 2 Test 2"),
                new ListItem("DDL 2 Test 3")
            };

            ddlSearchColumn1.DataSource = items1;
            ddlSearchColumn1.DataBind();

            ddlSearchColumn2.DataSource = items2;
            ddlSearchColumn2.DataBind();
        }
    }

    protected void ddlSearchColumn1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DropDownList list = sender as DropDownList;
        if (list == null || list.SelectedValue.ToLower() != "test 1") // OR WHATEVER YOUR CRITERIA IS
            return;

        ddlSearchColumn2.Items.FindByValue("DDL 2 Test 1").Attributes.Add("Disabled", "Disabled");
    }
}

IF you are interested in a client side solution:

With jQuery:

List 1: <asp:DropDownList ID="ddlSearchColumn1" runat="server" />
List 2: <asp:DropDownList ID="ddlSearchColumn2" runat="server" />

<script>
    jQuery('#<%= ddlSearchColumn1.ClientID %>').change(function ()
    {
        if (jQuery(this).val() != 'Test 1')//CHANGE YOUR CRITERIA
            return;

        jQuery('#<%= ddlSearchColumn2.ClientID %> option[value="DDL 2 Test 1"]').attr('disabled', 'disabled');
    });
</script>

Just using javascript no library:

List 1: <asp:DropDownList ID="ddlSearchColumn1" runat="server" />
List 2: <asp:DropDownList ID="ddlSearchColumn2" runat="server" />

<script>
    document.getElementById('<%= ddlSearchColumn1.ClientID %>').onchange = function ()
    {
        var orgDdl = document.getElementById('<%= ddlSearchColumn1.ClientID %>');
        var org2ddl = document.getElementById('<%= ddlSearchColumn2.ClientID %>');

        if (orgDdl.value != 'Test 1')
            return;

        for (var i = 0, ii = org2ddl.options.length; i < ii; i++)
        {
            if (org2ddl.options[i].value == "DDL 2 Test 1")
            {
                org2ddl.options[i].disabled = "disabled";
                break;
            }
        }
    };
</script>

Upvotes: 8

pseudocoder
pseudocoder

Reputation: 4392

The DropDownList contains a collection of ListItem objects, which have the property Enabled you are trying to set. This property works for ListItems in RadioButtonList or CheckBoxList controls, but NOT DropDownList.

MSDN reference: http://msdn.microsoft.com/en-us/library/vstudio/system.web.ui.webcontrols.listitem.enabled(v=vs.100).aspx

"Note: You cannot use this property to disable a ListItem control in a DropDownList control or ListBox control."

Edit: Answers above solve your problem as you described, and I learned something new :)

Upvotes: 0

Sandip Bantawa
Sandip Bantawa

Reputation: 2880

protected void ddlFirst_SelectedIndexChanged(object sender, EventArgs e)
    {
        foreach (ListItem item in ddlSecond.Items)
        {
            if (item.ToString() == ddlFirst.SelectedValue)
            {
                item.Attributes.Add("disabled", "disabled");
            }
        }
    }
    protected void ddlSecond_SelectedIndexChanged(object sender, EventArgs e)
    {
        foreach (ListItem item in ddlFirst.Items)
        {
            if (item.ToString() == ddlSecond.SelectedValue)
            {
                item.Attributes.Add("disabled", "disabled");
            }
        }
    }

But I still believe this is client side thing

Upvotes: 0

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