How to: Save Data in Project Files

A project subtype can save and retrieve subtype-specific data in the project file. The Managed Package Framework (MPF) provides two interfaces to accomplish this task:

• The IVsBuildPropertyStorage interface allows to access property values from the MSBuild section of the project file. The methods provided by IVsBuildPropertyStorage can be called by any user whenever the user needs to load or save build related data.

• The IPersistXMLFragment is used to persist non-build related data in free-form XML. The methods provided by IPersistXMLFragment are called by Visual Studio whenever Visual Studio needs to persist non-build related data in the project file.

For more information on how to persist build and non-build related data, see Persisting Data in the MSBuild Project File.

Saving and retrieving build related data

To save a build related data in the project file

• Call the SetPropertyValue method to save a full path of the project file.

  private SpecializedProject project;
  IVsBuildPropertyStorage projectStorage = (IVsBuildPropertyStorage)project;
  string newFullPath = GetNewFullPath();
  // Set a full path of the project file.
  ErrorHandler.ThrowOnFailure(projectStorage.SetPropertyValue(
      "MSBuildProjectDirectory",
      String.Empty,
      (uint)_PersistStorageType.PST_PROJECT_FILE, newFullPath));
  

To retrieve build related data from the project file

• Call the GetPropertyValue method to retrieve a full path of the project file.

  private SpecializedProject project;
  IVsBuildPropertyStorage projectStorage = (IVsBuildPropertyStorage)project;
  string fullPath;
  // Get a full path of the project file.
  ErrorHandler.ThrowOnFailure(projectStorage.GetPropertyValue(
      "MSBuildProjectDirectory",
      String.Empty,
      (uint)_PersistStorageType.PST_PROJECT_FILE, out fullPath));
  

Saving and retrieving non-build related data

To save non-build related data in the project file

1. Implement the IsFragmentDirty method to determine whether an XML fragment has changed since it was last saved to its current file.

   public int IsFragmentDirty(uint storage, out int pfDirty)
   {
       pfDirty = 0;
       switch (storage)
       {
           case (uint)_PersistStorageType.PST_PROJECT_FILE:
           {
               if (isDirty)
                   pfDirty |= 1;
               break;
           }
           case (uint)_PersistStorageType.PST_USER_FILE:
           {
               // We do not store anything in the user file.
               break;
           }
       }
   
       // Forward the call to inner flavor(s) 
       if (pfDirty == 0 && innerCfg != null && this.innerCfg is IPersistXMLFragment)
           return ((IPersistXMLFragment)this.innerCfg).IsFragmentDirty(storage, out pfDirty);
   
       return VSConstants.S_OK;
   
   }
   

2. Implement the Save method to save the XML data in the project file.

   public int Save(ref Guid guidFlavor, uint storage, out string pbstrXMLFragment, int fClearDirty)
   {
       pbstrXMLFragment = null;
   
       if (IsMyFlavorGuid(ref guidFlavor))
       {
           switch (storage)
           {
               case (uint)_PersistStorageType.PST_PROJECT_FILE:
               {
                   // Create XML for our data.
                   XmlDocument doc = new XmlDocument();
                   XmlNode root = doc.CreateElement(this.GetType().Name);
   
                   XmlNode node = doc.CreateElement(targetsTag);
                   node.AppendChild(doc.CreateTextNode(this.TargetsToExecute));
                   root.AppendChild(node);
   
                   node = doc.CreateElement(updateTargetsTag);
                   node.AppendChild(doc.CreateTextNode(this.UpdateTargetList.ToString()));
                   root.AppendChild(node);
   
                   doc.AppendChild(root);
                   // Get XML fragment representing our data
                   pbstrXMLFragment = doc.InnerXml;
   
                   if (fClearDirty != 0)
                       isDirty = false;
                   break;
               }
               case (uint)_PersistStorageType.PST_USER_FILE:
               {
                   // We do not store anything in the user file.
                   break;
               }
           }
       }
   
       // Forward the call to inner flavor(s)
       if (this.innerCfg != null && this.innerCfg is IPersistXMLFragment)
           return ((IPersistXMLFragment)this.innerCfg).Save(ref guidFlavor, storage, out pbstrXMLFragment, fClearDirty);
   
       return VSConstants.S_OK;
   }
   

To retrieve non-build related data in the project file

1. Implement the InitNew method to initialize the project extension properties and other build-independent data. This method is called if there is no XML configuration data present in the project file.

   public int InitNew(ref Guid guidFlavor, uint storage)
   {
       //Return,if it is our guid.
       if (IsMyFlavorGuid(ref guidFlavor))
           return VSConstants.S_OK;
   
       //Forward the call to inner flavor(s).
       if (this.innerCfg != null && this.innerCfg is IPersistXMLFragment)
           return ((IPersistXMLFragment)this.innerCfg).InitNew(ref guidFlavor, storage);
   
       return VSConstants.S_OK;
   

2. Implement the Load method to load the XML data from the project file.

   public int Load(ref Guid guidFlavor, uint storage, string pszXMLFragment)
   {
       if (IsMyFlavorGuid(ref guidFlavor))
       {
           switch (storage)
           {
               case (uint)_PersistStorageType.PST_PROJECT_FILE:
               {
                   // Load our data from the XML fragment.
                   XmlDocument doc = new XmlDocument();
                   XmlNode node = doc.CreateElement(this.GetType().Name);
                   node.InnerXml = pszXMLFragment;
                   if (node == null
                       || node.FirstChild == null
                       || node.FirstChild.ChildNodes.Count == 0
                       || node.FirstChild.ChildNodes[0].Name != targetsTag)
                       break;
                   this.TargetsToExecute = node.FirstChild.ChildNodes[0].InnerText;
   
                   if (node.FirstChild.ChildNodes.Count <= 1
                       || node.FirstChild.ChildNodes[1].Name != updateTargetsTag)
                       break;
                   this.UpdateTargetList = bool.Parse(node.FirstChild.ChildNodes[1].InnerText);
                   break;
               }
               case (uint)_PersistStorageType.PST_USER_FILE:
               {
                   // We do not store anything in the user file.
                   break;
               }
           }
       }
   
       // Forward the call to inner flavor(s)
       if (this.innerCfg != null && this.innerCfg is IPersistXMLFragment)
           return ((IPersistXMLFragment)this.innerCfg).Load(ref guidFlavor, storage, pszXMLFragment);
   
       return VSConstants.S_OK;
   }
   

Note

All code examples provided in this topic are parts of a larger example, ProjectSubtype.

See Also

Concepts

Persisting Data in the MSBuild Project File

Other Resources

ProjectSubtype