如何在GridView中行编辑时从数据库中加载下拉列表值？

// 在GridView的编辑模板中添加一个TemplateField
<asp:TemplateField HeaderText="下拉列表列">
    <EditItemTemplate>
        <asp:DropDownList ID="ddlOptions" runat="server" DataSourceID="dsOptions" DataTextField="OptionName" DataValueField="OptionValue"></asp:DropDownList>
    </EditItemTemplate>
    <ItemTemplate>
        <asp:Label ID="lblOption" runat="server" Text='<%# Eval("OptionName") %>'></asp:Label>
    </ItemTemplate>
</asp:TemplateField>

// 在GridView的RowEditing事件中设置编辑状态
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
    GridView1.EditIndex = e.NewEditIndex;
    GridView1.DataBind();
}

// 在GridView的RowDataBound事件中设置下拉列表的选中值
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowState == DataControlRowState.Edit)
    {
        DropDownList ddlOptions = (DropDownList)e.Row.FindControl("ddlOptions");
        string optionValue = ((DataRowView)e.Row.DataItem)["OptionValue"].ToString();
        ddlOptions.SelectedValue = optionValue;
    }
}