I use two types of project ,one is msi,the other is installscript,when I run the installation and use the custom option to give the user defined path,if the customer input a invalid path,the two types of project appears different forms.Can these two kinds of forms appear the same? Thank you.
It wouldn't be trivial to make them the same, no; the second (with error 1314) is provided by Microsoft's Windows Installer service. You might be able to catch the error case in the first one in your own InstallScript and use script to generate a dialog that looks like the 1314 error, but I would find that misleading. What's the motivation for wanting the corner case error dialogs to be the same? (I say corner case because most users who would be confused by either would use the browse button to select an existing folder, and thus won't see the error.)
