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我有一個LinkButton的頁面，點擊時，我想添加一個UserControl到頁面。我需要能夠添加/刪除儘可能多的用戶喜歡的控件。 Usercontrol由三個下拉列表組成。第一個下拉列表將其auotpostback屬性設置爲true，並掛接OnSelectedIndexChanged事件，該事件在被觸發時將使用適當的值加載剩餘的兩個下拉列表。保存狀態動態用戶控件...幫助！
我的問題是，無論在哪裏我把代碼在主機頁面，用戶控件沒有正確加載。我知道我必須在每個回發中重新創建usercontrols，並且創建了一個在託管頁面OnPreInit方法中執行的方法。我仍然收到以下錯誤： 無法在DataBind，Init，Load，PreRender或Unload階段修改控件集合。
這裏是我的代碼： 謝謝!!!!
bool createAgain = false;
IList<FilterOptionsCollectionView> OptionControls
{
get
{
if (SessionManager.Current["controls"] != null)
return (IList<FilterOptionsCollectionView>)SessionManager.Current["controls"];
else
SessionManager.Current["controls"] = new List<FilterOptionsCollectionView>();
return (IList<FilterOptionsCollectionView>)SessionManager.Current["controls"];
}
set
{
SessionManager.Current["controls"] = value;
}
}
protected void Page_Load(object sender, EventArgs e)
{
Master.Page.Title = Title;
LoadViewControls(Master.MainContent, Master.SideBar, Master.ToolBarContainer);
}
protected override void OnPreInit(EventArgs e)
{
base.OnPreInit(e);
System.Web.UI.MasterPage m = Master;
Control control = GetPostBackControl(this);
if ((control != null && control.ClientID ==
(lbAddAndCondtion.ClientID) || createAgain))
{
createAgain = true;
CreateUserControl(control.ID);
}
}
protected void AddAndConditionClicked(object o, EventArgs e)
{
var control = LoadControl("~/Views/FilterOptionsCollectionView.ascx");
OptionControls.Add((FilterOptionsCollectionView)control);
control.ID = "options" + OptionControls.Count.ToString();
phConditions.Controls.Add(control);
}
public event EventHandler<Insight.Presenters.PageViewArg> OnLoadData;
private Control FindControlRecursive(Control root, string id)
{
if (root.ID == id)
{
return root;
}
foreach (Control c in root.Controls)
{
Control t = FindControlRecursive(c, id);
if (t != null)
{
return t;
}
}
return null;
}
protected Control GetPostBackControl(System.Web.UI.Page page)
{
Control control = null;
string ctrlname = Page.Request.Params["__EVENTTARGET"];
if (ctrlname != null && ctrlname != String.Empty)
{
control = FindControlRecursive(page, ctrlname.Split('$')[2]);
}
else
{
string ctrlStr = String.Empty;
Control c = null;
foreach (string ctl in Page.Request.Form)
{
if (ctl.EndsWith(".x") || ctl.EndsWith(".y"))
{
ctrlStr = ctl.Substring(0, ctl.Length - 2);
c = page.FindControl(ctrlStr);
}
else
{
c = page.FindControl(ctl);
}
if (c is System.Web.UI.WebControls.CheckBox ||
c is System.Web.UI.WebControls.CheckBoxList)
{
control = c;
break;
}
}
}
return control;
}
protected void CreateUserControl(string controlID)
{
try
{
if (createAgain && phConditions != null)
{
if (OptionControls.Count > 0)
{
phConditions.Controls.Clear();
foreach (var c in OptionControls)
{
phConditions.Controls.Add(c);
}
}
}
}
catch (Exception ex)
{
throw ex;
}
}
下面是用戶控件的代碼：
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="FilterOptionsCollectionView.ascx.cs" Inherits="Insight.Website.Views.FilterOptionsCollectionView" %>
namespace Insight.Website.Views
{ [ViewStateModeById] 公共部分類FilterOptionsCollectionView：System.Web.UI.UserControl { 保護無效的Page_Load（對象發件人，EventArgs的） {
}
protected override void OnInit(EventArgs e)
{
LoadColumns();
ddlColumns.SelectedIndexChanged += new RadComboBoxSelectedIndexChangedEventHandler(ColumnsSelectedIndexChanged);
base.OnInit(e);
}
protected void ColumnsSelectedIndexChanged(object o, EventArgs e)
{
LoadCriteria();
}
public void LoadColumns()
{
ddlColumns.DataSource = User.GetItemSearchProperties();
ddlColumns.DataTextField = "SearchColumn";
ddlColumns.DataValueField = "CriteriaSearchControlType";
ddlColumns.DataBind();
LoadCriteria();
}
private void LoadCriteria()
{
var controlType = User.GetItemSearchProperties()[ddlColumns.SelectedIndex].CriteriaSearchControlType;
var ops = User.GetItemSearchProperties()[ddlColumns.SelectedIndex].ValidOperators;
ddlOperators.DataSource = ops;
ddlOperators.DataTextField = "key";
ddlOperators.DataValueField = "value";
ddlOperators.DataBind();
switch (controlType)
{
case ResourceStrings.ViewFilter_ControlTypes_DDL:
criteriaDDL.Visible = true;
criteriaText.Visible = false;
var crit = User.GetItemSearchProperties()[ddlColumns.SelectedIndex].SearchCriteria;
ddlCriteria.DataSource = crit;
ddlCriteria.DataBind();
break;
case ResourceStrings.ViewFilter_ControlTypes_Text:
criteriaDDL.Visible = false;
criteriaText.Visible = true;
break;
}
}
public event EventHandler OnColumnChanged;
public ISearchCriterion FilterOptionsValues { get; set; }
}
}