feat(namespace): update RootNamespace and AssemblyName in project file (#16)

Author: CalvinAllen

src/CodingWithCalvin.ProjectRenamifier/CodingWithCalvin.ProjectRenamifier.csproj

@@ -70,6 +70,7 @@
       <DependentUpon>RenameProjectDialog.xaml</DependentUpon>
     </Compile>
     <Compile Include="ProjectRenamifierPackage.cs" />
+    <Compile Include="Services\ProjectFileService.cs" />
     <Compile Include="source.extension.cs">
       <AutoGen>True</AutoGen>
       <DesignTime>True</DesignTime>
@@ -109,6 +110,7 @@
     <Reference Include="System" />
     <Reference Include="System.Design" />
     <Reference Include="System.ComponentModel.Composition" />
+    <Reference Include="System.Xml" />
     <Reference Include="System.Xaml" />
     <Reference Include="PresentationCore" />
     <Reference Include="PresentationFramework" />

src/CodingWithCalvin.ProjectRenamifier/Commands/RenamifyProjectCommand.cs

@@ -2,6 +2,7 @@
 using System.IO;
 using System.Windows.Interop;
 using CodingWithCalvin.ProjectRenamifier.Dialogs;
+using CodingWithCalvin.ProjectRenamifier.Services;
 using EnvDTE;
 using EnvDTE80;
 
@@ -78,11 +79,13 @@ private void RenameProject(Project project, DTE2 dte)
             }
 
             var newName = dialog.NewProjectName;
+            var projectFilePath = project.FullName;
 
-            // TODO: Implement the actual rename operation
+            // Update RootNamespace and AssemblyName in .csproj
+            ProjectFileService.UpdateProjectFile(projectFilePath, currentName, newName);
+
+            // TODO: Implement remaining rename operations
             // See open issues for requirements:
-            // - #6: Update RootNamespace in .csproj
-            // - #7: Update AssemblyName in .csproj
             // - #8: Update namespace declarations in source files
             // - #9: Update using statements across solution
             // - #11: Solution folder support

src/CodingWithCalvin.ProjectRenamifier/Services/ProjectFileService.cs

@@ -0,0 +1,78 @@
+using System.Xml;
+
+namespace CodingWithCalvin.ProjectRenamifier.Services
+{
+    /// <summary>
+    /// Service for updating project file (.csproj) elements.
+    /// </summary>
+    internal static class ProjectFileService
+    {
+        /// <summary>
+        /// Updates the RootNamespace and AssemblyName elements in a project file
+        /// if they match the old project name.
+        /// </summary>
+        /// <param name="projectFilePath">Full path to the .csproj file.</param>
+        /// <param name="oldName">The old project name to match against.</param>
+        /// <param name="newName">The new project name to set.</param>
+        /// <returns>True if any changes were made, false otherwise.</returns>
+        public static bool UpdateProjectFile(string projectFilePath, string oldName, string newName)
+        {
+            var doc = new XmlDocument();
+            doc.PreserveWhitespace = true;
+            doc.Load(projectFilePath);
+
+            var modified = false;
+
+            modified |= UpdateElement(doc, "RootNamespace", oldName, newName);
+            modified |= UpdateElement(doc, "AssemblyName", oldName, newName);
+
+            if (modified)
+            {
+                doc.Save(projectFilePath);
+            }
+
+            return modified;
+        }
+
+        /// <summary>
+        /// Updates a specific element in the project file if its value matches the old name.
+        /// </summary>
+        private static bool UpdateElement(XmlDocument doc, string elementName, string oldName, string newName)
+        {
+            // Handle both SDK-style (no namespace) and legacy (with namespace) project files
+            var namespaceManager = new XmlNamespaceManager(doc.NameTable);
+            var msbuildNs = "http://schemas.microsoft.com/developer/msbuild/2003";
+
+            // Check if document uses the MSBuild namespace
+            var hasNamespace = doc.DocumentElement?.NamespaceURI == msbuildNs;
+
+            XmlNodeList nodes;
+            if (hasNamespace)
+            {
+                namespaceManager.AddNamespace("ms", msbuildNs);
+                nodes = doc.SelectNodes($"//ms:{elementName}", namespaceManager);
+            }
+            else
+            {
+                nodes = doc.SelectNodes($"//{elementName}");
+            }
+
+            if (nodes == null || nodes.Count == 0)
+            {
+                return false;
+            }
+
+            var modified = false;
+            foreach (XmlNode node in nodes)
+            {
+                if (node.InnerText.Equals(oldName, StringComparison.OrdinalIgnoreCase))
+                {
+                    node.InnerText = newName;
+                    modified = true;
+                }
+            }
+
+            return modified;
+        }
+    }
+}