MSDN Magazine - July 2008 - (Page 64)

Figure 7 Updating Properties categoryEntity.Properties = new Dictionary (); categoryEntity.Properties["CategoryName"] = currentHdrNode.Text; int propCount = 1; if (e.Node.Parent != null) { //Loop through each node and add its category ID and //category name flex property. foreach (TreeNode node in e.Node.Parent.Nodes) { string listingIdPropName = string.Format ("ListingCategoryID{0}", propCount); string listingNamePropName = string.Format ("ListingCategoryName{0}", propCount); categoryEntity.Properties[listingIdPropName] = node.Name; categoryEntity.Properties[listingNamePropName] = node.Text; //if we are re-adding the updated category, the tree view //will still have its old value, so set the flex property //to the updated value if (node.Name == e.Node.Name) { categoryEntity.Properties[listingIdPropName] = m_OldSelectNode.Name; categoryEntity.Properties[listingNamePropName] = e.Label; } } propCount++; all the flex properties for the listing categories. Alternatively, you could have looped through each flex property and made the updates, but due to the simple structure of this entity, it’s easier to just recreate the entity as shown in Figure 7. To delete an entity or a container, point ServiceScope to the item and call the Delete method of SitkaSoapServiceClient. If it is a Header, delete the entire entity: if (m_OldSelectNode.Parent == null) { ssdsProxy.Delete(serviceScope); } For other entities, just as you did with the update, recreate the flex property collection and rebuild, performing the add for all nodes except the deleted node: SSDSClient.Entity categoryEntity = ssdsProxy.Get(serviceScope); categoryEntity.Properties = new Dictionary (); categoryEntity.Properties["CategoryName"] = CategoryName; int propCount = 1; foreach (TreeNode node in entityNode.Nodes) { string listingIdPropName = string.Format ("ListingCategoryID{0}", propCount); string listingNamePropName = string.Format ("ListingCategoryName{0}", propCount); if (node.Text != m_OldSelectNode.Text) { categoryEntity.Properties[listingIdPropName] = node.Name; categoryEntity.Properties[listingNamePropName] = node.Text; } propCount++; } //Submit the update to SSDS ssdsProxy.Update(serviceScope, categoryEntity); The next step is to add the listing categories. Since Contoso Classifieds uses a single entity to represent the entire collection of listing categories within a category header, you need to retrieve the category entity, add the additional listing categories (which will be added as additional flex properties), and submit the update to SSDS. To retrieve the category entity, set the scope to point directly to it and call the Get method, which will retrieve the entity directly without having to issue a query: SSDSClient.Scope serviceScope = new SSDSClient.Scope(); serviceScope.AuthorityId = "contosoclassifieds"; serviceScope.ContainerId = "Categories"; serviceScope.EntityId = CategoryID; //Retrieve the Category Entity SSDSClient.Entity categoryEntity = ssdsProxy.Get(serviceScope); } Finally, you will issue the update to SSDS and remove the node from the tree view: ssdsProxy.Update(serviceScope, categoryEntity); tvCategories.Nodes.Remove(m_OldSelectNode); Adding and Deleting Listing Schemas Now just determine the index of the new property, add it as an additional flex property, and issue the update (see Figure 6). Updating and Deleting Entities Updating listing categories is as simple as adding an additional flex property. For each update, you are required to retrieve the entity, make any updates locally and submit the update, passing the updated entity along with the scope to the Update method. Begin by setting the service scope to the main contosoclassifieds authority. Also point it to the Categories container and the entity for the category you are updating: SSDSClient.Scope serviceScope = new SSDSClient.Scope(); serviceScope.AuthorityId = "contosoclassifieds"; serviceScope.ContainerId = "Categories"; serviceScope.EntityId = currentHdrNode.Name; The current beta of SSDS does not support schemas. While there are plans to add schema support in the future, adding schemas yourself within SSDS is an easy task. The only caveat is that you need to manage the schema from within your application because, at this time, SSDS will not enforce it. For Contoso Classifieds, it seemed like a good idea for the administrator to define a custom schema for certain listing categories. You can define a schema inside the administrative client and use it later on when implementing the Web site. Up to this point there are no heterogeneous entities inside the same container. Since each entity has a Kind property, you can use Get the entity you are going to be updating: SSDSClient.Entity categoryEntity = ssdsProxy.Get(serviceScope); Now you can reinitialize the flex properties collection, re-adding 64 msdn magazine Figure 8 Schema Customization for a Listing SQL Server Data Services

Table of Contents Feed for the Digital Edition of MSDN Magazine - July 2008

MSDN Magazine - July 2008 Contents Toolbox CLR Inside Out Flex Your Data Data Points Advanced Basics Office Space Cutting Edge Data Services ADO.NET Data and WPF Transactions WCF P2P Test Run Security Briefs Foundations .NET Matters {End Bracket}

MSDN Magazine - July 2008

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