Asp.net error: Control 'ctl00 _ ctl00_contentplaceholder2_contentplaceholderright_listview1_ctrl0_del

Performance:

Of course, it may be that another control must be placed in the form.

 

Cause:

In normal cases, you can add a form directly, but if you use the master page, the real cause of this error is that the contentplaceholder in the master page is mistakenly placed outside <form>:

 

<Form ID = "form1" runat = "server">
<Asp: linkbutton id = "PB" runat = "server"> <B> P </B> roduct backlog </ASP: linkbutton>
<Asp: linkbutton id = "SB" runat = "server"> <B> S </B> Print backlog </ASP: linkbutton>
</Form>

<Asp: contentplaceholder id = "contentplaceholder1" runat = "server">
</ASP: contentplaceholder>
<Asp: contentplaceholder id = "contentplaceholder2" runat = "server">
</ASP: contentplaceholder>

 

Changed:

 

<Form ID = "form1" runat = "server">
<Asp: linkbutton id = "PB" runat = "server"> <B> P </B> roduct backlog </ASP: linkbutton>
<Asp: linkbutton id = "SB" runat = "server"> <B> S </B> Print backlog </ASP: linkbutton>

<Asp: contentplaceholder id = "contentplaceholder1" runat = "server">
</ASP: contentplaceholder>
<Asp: contentplaceholder id = "contentplaceholder2" runat = "server">
</ASP: contentplaceholder>
</Form>

Everything works.