MsiLocateComponent得到软件安装路径为空

[mibolt]

代码如下，但是返回的路径为空，求高手指教
public Window1()
{
InitializeComponent();
string componetCode = "{052CFB79-9D62-42E3-8A15-DE66C2C97C3E}";//QQ
listview1.Items.Add(GetComponent(componetCode));
}
[DllImport("MSI.DLL", CharSet = CharSet.Unicode)]
private static extern UInt32 MsiLocateComponent(string szComponent, StringBuilder lpPathBuf, ref int pcchBuf);

private static string GetComponent(string component)
{
int pathLength = 1024;
StringBuilder path = new StringBuilder(pathLength);
MsiLocateComponent(component, path, ref pathLength);
return path.ToString();
}