使用占位符动态地将用户控件添加到页面

Question

我正在尝试将用户控件添加到占位符。我将用户控件放在列表项<li> userControl </li>中，然后将列表项放在无序列表<ul><li>用户控件</li></ul>中，然后添加无序列表到占位符，phMain.Controls.Add（myUnorderedList）...代码如下：

var myListItem = new HtmlGenericControl("li");
var preview = new UserControls_ChiotsPreview();
preview = (UserControls_ChiotsPreview)LoadControl(typeof(UserControls_ChiotsPreview), null);
myListItem.Controls.Add(preview);
myUnorderedList.Controls.Add(myListItem);
placeholderMain.Controls.Add(myUnorderedList);

Answer 1

我弄明白了，这是我在页面上加载控件并调用构造函数逻辑的顺序，这导致我的控件具有空值。

var myUnorderedList = new HtmlGenericControl("ul");
myUnorderedList.Attributes["class"] = "resultClass";
var counter = 0;

foreach (var chiot in chiots)
{
//create list item, can I put the user control inside of here? why not?
var myListItem = new HtmlGenericControl("li");

//add user control to li
var preview = (UserControls_ChiotsPreview)LoadControl("~/UserControls/ChiotsPreview.ascx");
preview.Name = chiot.Name;
preview.MainPhoto = chiot.MainImage;
preview.Breed = chiot.Breed;
preview.ChampionSireDam = ResolveImage(chiot.ChampionSireDam);
preview.ChampionBloodline = ResolveImage(chiot.ChampionBloodline);
preview.Price = chiot.Price;
preview.Details = chiot.Description;

myListItem.Controls.Add(preview);

//add li to ul
myUnorderedList.Controls.Add(myListItem);

//max column  = 5
counter += 1;

//maximum 5 columns
if (counter == 5 || chiots.Count == counter)
{
try
{
phMain.Controls.Add(myUnorderedList);