fix http://community.sharpdevelop.net/forums/p/15856/41473.aspx - Null Reference at Set as StartUp Project

src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/Commands/ProjectNodeCommands.cs

@@ -12,13 +12,12 @@ namespace ICSharpCode.SharpDevelop.Project.Commands
 	{
 		public override void Run()
 		{
-			AbstractProjectBrowserTreeNode node  = ProjectBrowserPad.Instance.SelectedNode;
 			Solution solution = ProjectService.OpenSolution;
-			if (node == null || solution == null) {
+			IProject project = ProjectService.CurrentProject;
+			if (solution == null || project == null)
 				return;
-			}
+			if (project.IsStartable) {
-			if (node.Project.IsStartable) {
+				solution.Preferences.StartupProject = project;
-				solution.Preferences.StartupProject = node.Project;
 			} else {
 				MessageService.ShowError("${res:BackendBindings.ExecutionManager.CantExecuteDLLError}");
 			}
@@ -34,15 +33,14 @@ namespace ICSharpCode.SharpDevelop.Project.Commands
 
 		internal static void DoRunProject(bool withDebugging = true)
 		{
-			AbstractProjectBrowserTreeNode node = ProjectBrowserPad.Instance.SelectedNode;
+			IProject project = ProjectService.CurrentProject;
-			if (node == null) {
+			if (project == null)
 				return;
-			}
+			if (project.IsStartable) {
-			if (node.Project.IsStartable) {
+				BuildProjectBeforeExecute build = new BuildProjectBeforeExecute(project);
-				BuildProjectBeforeExecute build = new BuildProjectBeforeExecute(node.Project);
 				build.BuildComplete += delegate {
 					if (build.LastBuildResults.ErrorCount == 0) {
-						node.Project.Start(withDebugging);
+						project.Start(withDebugging);
 					}
 				};
 				build.Run();

src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/AbstractProjectBrowserTreeNode.cs

@@ -51,8 +51,8 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		/// <summary>
 		/// Returns the project in which this node belongs to. This assumes that
-		/// any node is child of a project. THIS DON'T WORK ON COMBINE NODES!
+		/// any node is child of a project. Keep in mind that Solution Folders 
-		/// (a combine node returns null)
+		/// and Solution Items do not have a project assigned.
 		/// </summary>
 		public virtual IProject Project {
 			get {

src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/ProjectNode.cs

@@ -43,6 +43,8 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		public ProjectNode(IProject project)
 		{
+			if (project == null)
+				throw new ArgumentNullException("project");
 			sortOrder = 1;
 			
 			this.ContextmenuAddinTreePath = "/SharpDevelop/Pads/ProjectBrowser/ContextMenu/ProjectNode";