More improvements to revision history

Show initial SHA when it differs from the HEAD
Rewrote show changelist using LINQ
Implemented show Next, Previous and HEAD differences
Handle copy selected text from a changelist

FormRevisionHistory.cs

@@ -22,6 +22,11 @@ public partial class FormRevisionHistory : Form
         /// </summary>
         private string _file;
 
+        /// <summary>
+        /// The current SHA string to initialize the list
+        /// </summary>
+        public string Sha { private get; set; }
+
         /// <summary>
         /// 2 last recently selected SHA submits
         /// </summary>
@@ -40,6 +45,7 @@ public FormRevisionHistory(string file)
                 statusStrip.SizingGrip = false;
 
             _file = file;
+            Sha = String.Empty;
             Text = @"Revision History for //" + file;
         }
 
@@ -85,8 +91,12 @@ private void FormRevisionHistoryLoad(object sender, EventArgs e)
             if(result.Success())
                 PanelRevlist.UpdateList(listRev, result.stdout);
 
-            // Activate the first item
-            listRev.SelectedIndices.Add(0);
+            // Activate the given SHA item or the first one if none given
+            int index = listRev.Items.IndexOfKey(Sha);
+            if (index < 0)
+                index = 0;
+            listRev.SelectedIndices.Add(index);
+            listRev.Items[index].EnsureVisible();
         }
 
         /// <summary>
@@ -256,7 +266,14 @@ private string GetTempFile(string file, string sha)
             // Create a temp file based on our file and write content to it
             file = file.Replace(Path.DirectorySeparatorChar, '_');
             string temp = Path.Combine(Path.GetTempPath(), sha) + "_" + file;
-            File.WriteAllText(temp, response);
+            try
+            {
+                File.WriteAllText(temp, response);
+            }
+            catch (Exception ex)
+            {
+                MessageBox.Show(ex.Message, "System error", MessageBoxButtons.OK, MessageBoxIcon.Error);
+            }
 
             // Add the temp file to the global list of temp files to be removed at the app exit time
             ClassGlobals.TempFiles.Add(temp);