Question

Master.cs文件

    ChatUserControl user1 = new ChatUserControl();
                         ChatUserControl user2 = new ChatUserControl();
                         ChatUserControl user3 = new ChatUserControl();
                         divChatUserControlCover.Controls.Add(user1);
                         divChatUserControlCover.Controls.Add(user2);
                         divChatUserControlCover.Controls.Add(user3);

private void BindUserControls()
            {

                                 ChatUserControl user1 = divChatUserControlCover.FindControl("user1") as ChatUserControl;
             }

ChatUserControl.cs

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="ChatUserControl.ascx.cs"
    Inherits="MetamorphismApp.ChatUserControl" %>

<asp:Timer ID="timer1" runat="server" OnTick="timer1_Tick" Interval="5000">
</asp:Timer>
<div id="divChatWindow" class="clChatWindow">
    <div>
        <asp:Label runat="server" Text='<%# Eval("username") %>' class="divHeader" ID="lblChatFriend"></asp:Label>
        <asp:Image ID="imgFriend" runat="server" CssClass="classFriendImage" />
        <asp:LinkButton ID="lbClose" runat="server" CommandName="Close" CssClass="lbClose"
            OnClick="lbClose_Click">Close</asp:LinkButton></div>
    <div class="chatText" id="idChatText" runat="server">
        <asp:UpdatePanel ID="UpdatePanel" runat="server">
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="timer1" EventName="Tick" />
                <asp:AsyncPostBackTrigger ControlID="btnSendChat" EventName="Click" />
            </Triggers>
            <ContentTemplate>
                <asp:Repeater runat="server" ID="rpChatMessages">
                    <ItemTemplate>
                        <asp:Image ID="imageForFriend" runat="server" CssClass="clFriendsImage" ImageUrl='<%# "HttpImageHandler.jpg?username=" +  DataBinder.Eval(Container.DataItem,"fromusername").ToString() %>' />
                        <asp:Label ID="chatMessage" runat="server" Text='<%# Eval("Message") %>'></asp:Label>
                        <br>
                    </ItemTemplate>
                </asp:Repeater>
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>
    <asp:TextBox ID="txtChatMessage" runat="server" Width="142px" CssClass="clChatMessage" EnableViewState="true"
        TextMode="MultiLine"></asp:TextBox>
    <asp:LinkButton ID="btnSendChat" runat="server" CommandName="Insert" CommandArgument='<%# Eval("username") %>'
        OnClick="btnSendChat_Click">Send</asp:LinkButton>

</div>

Master.cs

private void BindUserControls()
        {

                             ChatUserControl user1 = divChatUserControlCover.FindControl("user1") as ChatUserControl;
         }

我在user1控件的BindUserControls中出错;对象引用未设置为对象的实例

Answer 1

最有可能的是，没有调用实例化并将控件放入div的代码。确保即使在回发时也创建了控件，以便可以触发/处理更多事件。

Answer 2

应在每个回发中重新创建（正确）动态控件。我通常会在Init或LoadViewState中重新创建它们。

另请参阅this

Answer 3

用户控件无法按照我的方式实例化。还有另一种方法可以做到这一点。那就是使用Page_LoadControl方法。

用户控件未实例化

3 个答案: