Ensuring DisplayValue is set to a value when null (#292)

* Ensuring DisplayValue is set to a value when null

* Changes that *actually do something!*

* Changes that *actually do something!*

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.cs

@@ -205,6 +205,14 @@ namespace Microsoft.SqlTools.ServiceLayer
             }
         }
 
+        public static string QueryServiceCellNull
+        {
+            get
+            {
+                return Keys.GetString(Keys.QueryServiceCellNull);
+            }
+        }
+
         public static string QueryServiceRequestsNoQuery
         {
             get
@@ -1013,6 +1021,9 @@ namespace Microsoft.SqlTools.ServiceLayer
             public const string QueryServiceColumnNull = "QueryServiceColumnNull";
 
 
+            public const string QueryServiceCellNull = "QueryServiceCellNull";
+
+
             public const string QueryServiceRequestsNoQuery = "QueryServiceRequestsNoQuery";
 
 

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.resx

@@ -245,6 +245,10 @@
     <value>(No column name)</value>
     <comment></comment>
   </data>
+  <data name="QueryServiceCellNull" xml:space="preserve">
+    <value>NULL</value>
+    <comment></comment>
+  </data>
   <data name="QueryServiceRequestsNoQuery" xml:space="preserve">
     <value>The requested query does not exist</value>
     <comment></comment>

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings

@@ -101,6 +101,8 @@ QueryServiceQueryFailed(string message) = Query failed: {0}
 
 QueryServiceColumnNull = (No column name)
 
+QueryServiceCellNull = NULL
+
 QueryServiceRequestsNoQuery = The requested query does not exist
 
 QueryServiceQueryInvalidOwnerUri = This editor is not connected to a database

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.xlf

@@ -596,6 +596,11 @@
         <target state="new">Result limit cannot be negative</target>
         <note></note>
       </trans-unit>
+      <trans-unit id="QueryServiceCellNull">
+        <source>NULL</source>
+        <target state="new">NULL</target>
+        <note></note>
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/DataStorage/ServiceBufferFileStreamReader.cs

@@ -198,7 +198,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.DataStorage
             if (isNullFunc == null ? length.ValueLength == 0 : isNullFunc(length.TotalLength))
             {
                 result.RawObject = null;
-                result.DisplayValue = null;
+                result.DisplayValue = SR.QueryServiceCellNull;
                 result.IsNull = true;
             }
             else