我有一个页面,我在其中动态加载用户控件,如下所示:
Default.aspx的:
<cc1:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</cc1:ToolkitScriptManager>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
Default.aspx.cs:
protected void Page_Load(object sender, EventArgs e)
{
var ctrl = LoadControl("~/UserCtrl1.ascx");
ctrl.ID = "ucUserCtrl1";
PlaceHolder1.Controls.Add(ctrl);
}
以下是 UserCtrl1.ascx
的代码
<asp:Label ID="Label1" runat="server"></asp:Label>
<asp:Button ID="Button1" runat="server" Text="Button1" OnClick="Button1_Click" />
<br />
<asp:PlaceHolder ID="PlaceHolder2" runat="server"></asp:PlaceHolder>
单击Button1时,我正在动态加载另一个用户控件
UserCtrl1.ascx.cs
protected void Button1_Click(object sender, EventArgs e)
{
Label1.Text = "UserControl - 1 button clicked!";
var ctrl = LoadControl("~/UserCtrl2.ascx");
ctrl.ID = "ucUserCtrl2";
PlaceHolder2.Controls.Add(ctrl);
}
以下是UserCtrl2.ascx的标记
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label ID="Label2" runat="server"></asp:Label>
<asp:Button ID="Button2" runat="server" Text="Button2" OnClick="Button2_Click" />
</ContentTemplate>
</asp:UpdatePanel>
UserCtrl2.ascx.cs
protected void Button2_Click(object sender, EventArgs e)
{
Label2.Text = "UserControl - 2 button clicked!";
}
当我在UserCtrl1中单击Button1加载页面后,click事件将触发,我可以看到Label1文本。它也正确加载了UserCtrl2,但是当我点击UserCtrl2中的Button2时,点击事件就会触发,甚至更糟糕的是当我单击Button2两次时,UserCtrl2控件从页面中消失。我怎样才能解决这个问题?
答案 0 :(得分:3)
第二个控件的问题在于,只有在点击按钮1后才会丢失它。但是当其他一些(不是按钮1点击)回发时,你的第二个控件没有加载。
其中一个可能的修复方法是保存一些标记(例如在ViewState中),它将帮助您确定是否应加载第二个控件(并在页面加载时加载)。
protected void Button1_Click(object sender, EventArgs e)
{
Label1.Text = "UserControl - 1 button clicked!";
var ctrl = LoadControl("~/UserCtrl2.ascx");
ctrl.ID = "ucUserCtrl2";
PlaceHolder2.Controls.Add(ctrl);
this.SecondControlLoaded = true; // This flag saves to ViewState that your control was loaded.
}
protected void Page_Load(object sender, EventArgs e)
{
var ctrl = LoadControl("~/UserCtrl1.ascx");
ctrl.ID = "ucUserCtrl1";
PlaceHolder1.Controls.Add(ctrl);
if (this.SecondControlLoaded)
{
var ctrl = LoadControl("~/UserCtrl2.ascx");
ctrl.ID = "ucUserCtrl2";
PlaceHolder2.Controls.Add(ctrl);
}
}