I got a master page with a content place holder (called: placeForButtons). In one of my forms a panel (called: uxButtonsPanel) is added as one of its controls . Later when the program is running (after it compiled what it had successfully) I try to add a button( called: uxInteractionButton0) to that panel.
the following error is shown:
Control 'ctl00_placeForButtons_uxInteractionButt… of type 'Button' must be placed inside a form tag with runat=server.
You aren't technically posting in the right place, that appears to be a asp.net question written in C#, there is an asp.net forum here at daniweb for that. you might get better help there.
the error states your code should have the <%runat="server"%> tag.
but it could also be that you didn't name your button with the "name" property, and also your click event code is incorrect. the correct syntax for adding a button click event in C# is button1.Click +=new EventHandler(button1_Click); but I cannot be sure, as I don't frequently use asp.net, my web server only supports classic asp. and I write C# forms applications.
Post the contents for the master page and the content form for the master page. That is a rather odd error because the content place holder needs to be inside of a server tag .. so i'm not sure why the button wouldn't fall under that either unless your page declaration isn't runat="server" for the nested page.