Using DropDownList in EditTemplates of a GridView

Question

I am working on a GridView in Asp.Net. When initially a the Page Loads, my gridview look like:

When a user clicks, to edit a row, I am using edit templates to show 'Domain' in a DropDownList. But problem is , when the DropDownlist gets load with data, it lost the current value of the 'Domain'.
i.e If I want to edit 4th Row, its domain which is currently set to 'Computers' is getting changed to 'MBA' which is ofcourse the first element return by the DataSource.

I want to display the current value ('computers') as the selected value in DropDownList. But I am unable to get the value of Domain, which is being edited.

Answer 1

Hey,

You can bind the SelectedValue property of the dropdown as in:

SelectedValue='<%# Eval("Domain") %>'

However, if you bind a value that doesn't exist, an exception will be thrown. So you may need to handle in code depending on your scenario.

EDIT: if the value doesn't exist, the unfortunate remaining solution will be tap into the gridview's RowDataBound and get the reference to the drop down, and do:

MyBoundObject obj = (MyBoundObject)e.Row.DataItem;
DropDownList ddl = (DropDownList)e.Row.Cells[<index>].FindControl("ddl1");
ListItem item = ddl.Items.FindByValue(obj.Domain);
if (item != null) item.Selected = true;

Here, only if the list item exists it is selected. If that doesn't select the item, try ddl.SelectedValue = item.Value.

HTH.

Answer 2

to solve exception use AppendDataBoundItems="true".

<asp:DropDownList ID="ddlCategory" runat="server" SelectedValue='<%# Eval("Domain") %>' 
        DataSourceID="datasource"
            DataTextField="text" DataValueField="value" AppendDataBoundItems="true">
            <asp:ListItem Text="Select..." Value=""></asp:ListItem>
        </asp:DropDownList>

Answer 3

This may help you:

Listen to the event RowEditing, get the Dropdownlist of the specific row using the .FindControl() Method and perform an explicit .DataBind() on the DDL.