Improve perfrormance of WP7 multiple IsolatedStorageFile.ExistDirectory calls

In my new project, I need to check the isolated storage to get if the Directory is exist, but if the directories have the same parent directory, we can first call isf.GetDirectoryNames(Path.Combine(“Downloads”, “*”)); to get the directories and then using strings.contain(xxx), after all, performance is fine.

With a lot of isf.DirectoryExists:
About cost 1.1s
With GetDirectoryNames and strings.contain(xxx)
After change the code, cost 0.11s.

How to create a branch from WP78 to 80

Please following these steps: 
1.right the trunk(include WP78 repository), choose branch/Tags 
2.navigate the combobox to “branch/80” ok. the solution, update the specified project 
5.remove the WP78 tiles from App.xaml 
6.remove the unavailable references and replace them. 
7.remove the package.config, it`s just contain WP78 nuget informations. the nuget packages. 
9.if you meet the vm:Locator not exist, you can update the MVVMLight using nuget, after all error has fixed, you can see the not exist error is disappeared. 
10.commit the new solution.

How to merge WP 71/80 repository with TortoriseSVN?

Here is the following steps :
1.navigate to 80(branch)
2.Right click choose merge
3.choose “Merge a range of revisions”
4.Choose all revision
5.choose merge.
6.If you meet collision(such as WMManifest.xml), choose prep local.