Reference WixUI Error

Reference WixUI Error

Enviorment:Win7+VS2012+Wix3.7 Complile error. Unresolved reference to
symbol 'WixUI:WixUI_InstallDir' in section
'Product:{9E327731-0EAC-4A02-9C3C-9C136ACCE05B}'
Code is the follow:
<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Product Id="{9E327731-0EAC-4A02-9C3C-9C136ACCE05B}"
Name="SetupProject2" Language="1033" Version="1.1.1.1"
Manufacturer="Anser" UpgradeCode="61eb40a6-21d9-4f23-9c9e-078b98707371">
<Package InstallerVersion="200" Compressed="yes"
InstallScope="perMachine" />
<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName]
is already installed." />
<MediaTemplate />
<Feature Id="ProductFeature" Title="SetupProject2" Level="1">
<ComponentGroupRef Id="ProductComponents" />
</Feature>
<Property Id="WIXUI_INSTALLDIR">INSTALLDIR</Property>
<UIRef Id="WixUI_InstallDir"/>
</Product>
<Fragment>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFilesFolder">
<Directory Id="INSTALLFOLDER" Name="SetupProject2" />
</Directory>
</Directory>
</Fragment>
<Fragment>
<ComponentGroup Id="ProductComponents" Directory="INSTALLFOLDER">
<!-- TODO: Remove the comments around this Component element and the
ComponentRef below in order to add resources to this installer. -->
<!-- <Component Id="ProductComponent"> -->
<!-- TODO: Insert files, registry keys, and other resources here. -->
<!-- </Component> -->
<Component Id="ProductComponent" DiskId="1"
Guid="{65F464D6-BC0B-4679-9546-CF8B6CFCE184}">
<File Name='test.exe' Source="test.exe" />
</Component>
</ComponentGroup>
</Fragment>
</Wix>
I can't find the reason.Who can help me?