PlaceHolder Control in ASP.Net
The PlaceHolder Web server control does not have any visible output and is used
as a place holder when we add controls at run time. The PlaceHolder control is
used to reserve space for controls added by code.
PlaceHolder is a container of other web server control
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of using PlaceHolder is that the textbox, button and other content contained
within the PlaceHolder opening and closing HTML tags are kept as a single
entity. For example, to hide the entire search form (i.e. text label, textbox
and button) only a single line of C# code is required:
sender, EventArgs e)
PlaceHolder1.Visible = false;
Now when run the project then all control will
not show on the page because here PlaceHolder Visibility is
false; and all control are inside PlaceHolder.