Question

I have a asp.net dropdown control to which tool tip has been added. It works fine on the mouse over. I also have a Modal Popup in that page. When I open and close the Modal Popup the tool tip in the drop are no more shown.

Below is my code.

       <div class="col">
            <div class="labelname required">
                <asp:Label ID="lblsupplier" runat="server" Text="Supplier"></asp:Label>
            </div>
            <div class="labelvalue">
                <asp:DropDownList ID="DdlSupplier" TabIndex="11" runat="server" AutoPostBack="true"
                    CausesValidation="false" OnSelectedIndexChanged="DdlSupplier_SelectedIndexChanged">
                </asp:DropDownList>
                <asp:RequiredFieldValidator ID="reqSupplier" runat="server" ControlToValidate="DdlSupplier"
                    ValidationGroup="SubmitGroupMain" InitialValue="0" ErrorMessage="Please Select Supplier Name"
                    SetFocusOnError="true" Display="None"></asp:RequiredFieldValidator>
                <ajaxToolkit:ValidatorCalloutExtender ID="ValidatorCalloutExtender7" runat="Server"
                    TargetControlID="reqSupplier" HighlightCssClass="validatorCalloutHighlight">
                </ajaxToolkit:ValidatorCalloutExtender>
            </div>
            <asp:LinkButton runat="server" ID="lnkAddSupplier" CssClass="btnadd" ToolTip="New Supplier"
                OnClick="lnkAddSupplier_Click"></asp:LinkButton>
            <asp:Button runat="server" ID="popupshowAccount" Style="display: none" />
        </div>
    </div>

Code behind

foreach (ListItem item in DdlSupplier.Items)
            {
                item.Attributes.Add("title", item.Text);
            }
            DdlSupplier.Attributes.Add("onmouseover","this.title=this.options[this.selectedIndex].title");

Clicking on lnkAddSupplier opens up a popup. After closing the popup tool tip is not visible for the dropdown.

Please help on solving this issue.

Answer 1

Attributes won’t be saved in Viewstate and that’s why they will disappear across postbacks. Similar is the case with Custom Attributes.

That’s why we have to use DropDownList Pre Render event to set attributes

protected void DropDownList1_PreRender(object sender, EventArgs e)
{
    foreach (ListItem item in DropDownList1.Items)
        item.Attributes.Add("title", "Something to test!!!!!!");
}