ASP.Net PlaceHolder、Panel等控件未实现INamingContainer,导致FindControl无效
Panel spnButtons = new Panel();
Button btn = new Button();
btn.ID = "btn1";
spnButtons.Controls.Add(btn);
// 输出True,表示没有找到控件
Response.Write(spnButtons.FindControl(btn.ID) == null);
Panel spnButtons = new Panel();
Page.Controls.Add(spnButtons);// 创建Panel后把它加入Page
Button btn = new Button();
btn.ID = "btn1";
spnButtons.Controls.Add(btn);
// 输出False,表示找到了控件
Response.Write(spnButtons.FindControl(btn.ID) == null);
Repeater spnButtons = new Repeater();
Button btn = new Button();
btn.ID = "btn1";
spnButtons.Controls.Add(btn);
// 输出False,表示找到了控件
Response.Write(spnButtons.FindControl(btn.ID) == null);
查了一下Panel是继承于WebControl,而WebControl的定义是:
public class WebControl : Control, IAttributeAccessor
{}
Repeater的定义是:
public class Repeater : Control, INamingContainer
{}
难道是因为Repeater实现了INamingContainer的原因吗?
我又自定义了一个类,继承自Panel,并实现了INamingContainer,可以找到控件了:
代码如下:
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
myPanel spnButtons = new myPanel();
Button btn = new Button();
btn.ID = "btn1";
spnButtons.Controls.Add(btn);
Response.Write(spnButtons.FindControl(btn.ID) == null);
}
}
public class myPanel : Panel, INamingContainer
{
public myPanel():base()
{
}
}
上,ASP.Net中,PlaceHolder、Panel等控件未实现INamingContainer,导致FindControl无效
如果把这些控件加入到实现了INamingContainer的父控件中,或者用子类实现INamingContainer,就可以使FindControl有效了。