指数超出范围。必须是非负数且小于collection.Parameter name：index的大小 [英] Index was out of range. Must be non-negative and less than the size of the collection.Parameter name: index

问题描述

hi
可以帮我解决这个问题吗？将数据绑定到下拉列表。





html代码

hi can any one help me to solve this? am binding data to dropdownlist.


html code

<telerik:RadComboBox ID="cmbEPS" runat="server" Height="22px" Width="200px">
                                    <ItemTemplate>
                                        <div onclick="StopPropagation(event)">
                                            <asp:TreeView ID="tvWBS" runat="server" NodeStyle-NodeSpacing="2px"

                                                ShowLines="true">
                                                <HoverNodeStyle CssClass="CustomNodeColor" />
                                                <SelectedNodeStyle BackColor="#5B5B5B" ForeColor="White" HorizontalPadding="3px" />
                                                <NodeStyle ForeColor="#000000" />
                                            </asp:TreeView>
                                        </div>
                                    </ItemTemplate>
                                </telerik:RadComboBox>
                                <asp:RequiredFieldValidator ID="rfvActivityGroup" runat="server" ControlToValidate="cmbActivityGroup"

                                    Display="None" ErrorMessage="Select EPS" SetFocusOnError="True" ValidationGroup="g"

                                    Visible="true"></asp:RequiredFieldValidator>

.................... .................................................. .................................................. .................................................. ................................
in .cs

.......................................................................................................................................................................................................
in .cs

RadComboBox cmbEPS = (RadComboBox)phDynamic.FindControl("cmbEPS");
       if (cmbEPS !=null)
       {

               RadTreeView rtvEPS = (RadTreeView)cmbEPS.Items[0].FindControl("rtvEPS");//in this line am getting error..

谢谢

thank you

推荐答案

使用索引的该指令的唯一部分是Items集合。这意味着没有可供选择的项目。

在检查空控件时以及访问之前检查集合的大小。

The only part of that instruction using an index is the Items collection. Which implies there are no Items to select from.
Check the size of the collection when you check for a null control, and before you access it.

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