这是我的自定义控制代码:
namespace MyControlNameSpace
{
public class MyControlItemCommandEventArgs : CommandEventArgs
{
private MyControlItem _item;
private object _commandSource;
public MyControlItemCommandEventArgs(MyControlItem item, object commandSource, CommandEventArgs cea) : base(cea)
{
_item = item;
_commandSource = commandSource;
}
public MyControlItem Item { get{ return _item; } }
public object CommandSource { get{ return _commandSource; } }
}
public class MyControlItem : Control, IDataItemContainer
{
public MyControlItem(object dataItem, int index)
{
_dataItem = dataItem;
_dataItemIndex = _displayIndex = index;
}
private readonly object _dataItem;
private readonly int _dataItemIndex;
private readonly int _displayIndex;
public object DataItem { get { return _dataItem; } }
public int DataItemIndex { get { return _dataItemIndex; } }
public int DisplayIndex { get { return _displayIndex; } }
protected override bool OnBubbleEvent(object source, EventArgs args)
{
if (args is CommandEventArgs)
{
var e = new MyControlItemCommandEventArgs(this, source, (CommandEventArgs)args);
base.RaiseBubbleEvent(this, e);
return true;
}
return false;
}
}
public delegate void ItemEventHandler(object sender, MyControlItemCommandEventArgs e);
[DefaultProperty("Text")]
[ToolboxData("<{0}:MyControl runat=server></{0}:MyControl>")]
public class MyControl : CompositeDataBoundControl, IPrivilage
{
public event ItemEventHandler ItemCommand;
protected virtual void OnItemCommand(MyControlItemCommandEventArgs e)
{
if (ItemCommand != null)
ItemCommand(this, e);
}
protected override bool OnBubbleEvent(object source, EventArgs args)
{
// only bother bubbling appropriate events
if (args is MyControlItemCommandEventArgs)
{
OnItemCommand((MyControlItemCommandEventArgs)args);
return true;
}
return false;
}
protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)
{
// here I'm adding some controls like buttons and other
// Iterate for ItemTemplate
foreach (object dataItem in dataSource)
{
if (ItemTemplate != null)
{
// create instance of MyControlItem control
var item = new MyControlItem(dataItem, count++);
// instantiate in new item object
ItemTemplate.InstantiateIn(item);
// add item to Controls collection
Controls.Add(item);
// need to support <%# %> expressions
item.DataBind();
}
}
// some code here
}
}
在.aspx页面:
protected void Page_Load(object sender, EventArgs e)
{
// if it's not post back then get the data and assign to MyControl DataSource property
if(!IsPostBack)
GetData();
}
protected void MyControl1_OnItemCommand(object sender, MyControlItemCommandEventArgs e)
{
var x = e.DataItem;
// x here is always null;
}
正如您所看到的,当OnItemCommand事件时我无法获取e.DataItem,因为它始终为null。
我试图删除if(!IsPostBack)
中的Page_Load
,以便每次分页加载数据源时,但这不对,我应该能够分配数据源,如果它是PostBack
,就像在Asp.Net中一样Repeater
控制。
任何想法怎么做?
答案 0 :(得分:0)
OnItemCommand
事件在回发后引发。此时,如果CompositeDataBoundControl
启用了ViewState
,它将重新创建子控件而不查询数据库。我会调用CreateChildControls
方法,dataBinding
设置为false
,dataSource
将是null
对象的可枚举序列,用作实际的占位符数据
您将在任何数据绑定控件中获得相同的行为。如果您使用Repeater
尝试相同的操作,则会在e.Item.DataItem
事件中看到null
为ItemCommand
。