Fix scroll issues

WinAlfred/PluginLoader/PythonPluginWrapper.cs

@@ -11,7 +11,7 @@ namespace WinAlfred.PluginLoader
         private PluginMetadata metadata;
 
         [DllImport("PyWinAlfred.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
-        private extern static IntPtr ExecPython(string directory, string file,string method,string para);
+        private extern static IntPtr ExecPython(string directory, string file, string method, string para);
         [DllImport("PyWinAlfred.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
         private extern static void InitPythonEnv();
 
@@ -22,16 +22,25 @@ namespace WinAlfred.PluginLoader
 
         public List<Result> Query(Query query)
         {
-            string s = Marshal.PtrToStringAnsi(ExecPython(metadata.PluginDirecotry, metadata.ExecuteFileName.Replace(".py", ""),"query",query.RawQuery));
+            try
-            List<PythonResult> o = JsonConvert.DeserializeObject<List<PythonResult>>(s);
-            List<Result> r = new List<Result>();
-            foreach (PythonResult pythonResult in o)
             {
-               PythonResult ps = pythonResult;
+                string s = Marshal.PtrToStringAnsi(ExecPython(metadata.PluginDirecotry, metadata.ExecuteFileName.Replace(".py", ""), "query", query.RawQuery));
-                ps.Action = () => ExecPython(metadata.PluginDirecotry, metadata.ExecuteFileName.Replace(".py", ""),ps.ActionName,ps.ActionPara);
+                List<PythonResult> o = JsonConvert.DeserializeObject<List<PythonResult>>(s);
-                r.Add(ps);
+                List<Result> r = new List<Result>();
+                foreach (PythonResult pythonResult in o)
+                {
+                    PythonResult ps = pythonResult;
+                    ps.Action = () => ExecPython(metadata.PluginDirecotry, metadata.ExecuteFileName.Replace(".py", ""), ps.ActionName, ps.ActionPara);
+                    r.Add(ps);
+                }
+                return r;
             }
-            return r;
+            catch (Exception)
+            {
+
+                throw;
+            }
+
         }
 
         public void Init()

WinAlfred/ResultPanel.xaml

@@ -5,7 +5,7 @@
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
              mc:Ignorable="d" 
              d:DesignHeight="300" d:DesignWidth="300">
-    <ScrollViewer MaxHeight="300" VerticalScrollBarVisibility="Auto">
+    <ScrollViewer x:Name="sv" MaxHeight="300" VerticalScrollBarVisibility="Auto">
         <StackPanel x:Name="pnlContainer">
 
         </StackPanel>

WinAlfred/ResultPanel.xaml.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Windows;
 using System.Windows.Controls;
 using WinAlfred.Plugin;
 
@@ -89,9 +90,54 @@ namespace WinAlfred
         {
             if (pnlContainer.Children.Count > 0)
             {
+                int oldIndex = GetCurrentSelectedResultIndex();
+
                 UnSelectAll();
                 var resultItemControl = pnlContainer.Children[index] as ResultItem;
-                if (resultItemControl != null) resultItemControl.Selected = true;
+                if (resultItemControl != null)
+                {
+                    resultItemControl.Selected = true;
+
+                    double scrollPosition = 0;
+                    Point newItemBottomPoint = resultItemControl.TranslatePoint(new Point(0, resultItemControl.ActualHeight), pnlContainer);
+                    if (index == 0)
+                    {
+                        sv.ScrollToTop();
+                        return;
+                    }
+                    if (index == pnlContainer.Children.Count - 1)
+                    {
+                        sv.ScrollToBottom();
+                        return;
+                    }
+
+                    if (index < oldIndex)
+                    {
+                        //move up and old item is at the top of the scroll view 
+                        if ( newItemBottomPoint.Y - sv.VerticalOffset == 0)
+                        {
+                            scrollPosition = sv.VerticalOffset - resultItemControl.ActualHeight;
+                        }
+                        else
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        //move down and old item is at the bottom of scroll view
+                        if (sv.ActualHeight + sv.VerticalOffset == newItemBottomPoint.Y - resultItemControl.ActualHeight)
+                        {
+                            scrollPosition = newItemBottomPoint.Y - sv.ActualHeight;
+                        }
+                        else
+                        {
+                            return;
+                        }
+                    }
+
+                    sv.ScrollToVerticalOffset(scrollPosition);
+                }
             }
         }