Fix sample warnings seen during workflow build.

ContentModification/ChangeLinkColors/ChangeLinkColors.cs

@@ -52,7 +52,7 @@ static void Main(string[] args)
                     Annotation annot = page.GetAnnotation(i);
                     if (annot is LinkAnnotation)
                     {
-                        linkAnnots.Add(annot as LinkAnnotation);
+                        linkAnnots.Add((LinkAnnotation)annot);
                     }
                 }
 
@@ -92,7 +92,7 @@ static void FindAndProcessText(Content content, List<LinkAnnotation> linkAnnots)
                 else if (element is Text)
                 {
                     Console.WriteLine("Found a Text object.");
-                    CheckCharactersInText(element as Text, linkAnnots);
+                    CheckCharactersInText((Text)element, linkAnnots);
                 }
             }
         }

ContentModification/CreateLayer/CreateLayer.cs

@@ -43,34 +43,38 @@ static void Main(string[] args)
                 Console.WriteLine("Opened a document.");
 
                 Page pg = doc.GetPage(0);
-                Image img = (pg.Content.GetElement(0) as Image);
-
-                // Containers, Forms and Annotations can be attached to an
-                // OptionalContentGroup; other content (like Image) can
-                // be made optional by placing it inside a Container
-                Container container = new Container();
-                container.Content = new Content();
-                container.Content.AddElement(img);
-
-                // We replace the Image with the Container
-                // (which now holds the image)
-                pg.Content.RemoveElement(0);
-                pg.UpdateContent();
-
-                pg.Content.AddElement(container);
-                pg.UpdateContent();
-
-                // We create a new OptionalContentGroup and place it in the
-                // OptionalContentConfig.Order array
-                OptionalContentGroup ocg = CreateNewOptionalContentGroup(doc, "Rubber Ducky");
-
-                // Now we associate the Container with the OptionalContentGroup
-                // via an OptionalContentMembershipDict.  Note that we MUST
-                // update the Page's content afterwards.
-                AssociateOCGWithContainer(doc, ocg, container);
-                pg.UpdateContent();
-
-                doc.Save(SaveFlags.Full, sOutput);
+                Element element = pg.Content.GetElement(0);
+                if (element is Image)
+                {
+                    Image img = (Image)element;
+
+                    // Containers, Forms and Annotations can be attached to an
+                    // OptionalContentGroup; other content (like Image) can
+                    // be made optional by placing it inside a Container
+                    Container container = new Container();
+                    container.Content = new Content();
+                    container.Content.AddElement(img);
+
+                    // We replace the Image with the Container
+                    // (which now holds the image)
+                    pg.Content.RemoveElement(0);
+                    pg.UpdateContent();
+
+                    pg.Content.AddElement(container);
+                    pg.UpdateContent();
+
+                    // We create a new OptionalContentGroup and place it in the
+                    // OptionalContentConfig.Order array
+                    OptionalContentGroup ocg = CreateNewOptionalContentGroup(doc, "Rubber Ducky");
+
+                    // Now we associate the Container with the OptionalContentGroup
+                    // via an OptionalContentMembershipDict.  Note that we MUST
+                    // update the Page's content afterwards.
+                    AssociateOCGWithContainer(doc, ocg, container);
+                    pg.UpdateContent();
+
+                    doc.Save(SaveFlags.Full, sOutput);
+                }
             }
         }
 

ContentModification/ExtendedGraphicStates/ExtendedGraphicStates.cs

@@ -85,7 +85,7 @@ static void blendPage(Document doc, Image foregroundImage, Image backgroundImage
                 m = m.Scale(12.0, 12.0);
 
                 ExtendedGraphicState xgs = new ExtendedGraphicState();
-                TextRun tr = null;
+                TextRun? tr = null;
                 if (i == 0)
                 {
                     xgs.BlendMode = BlendMode.Normal;

Images/DocToImages/DocToImages.cs

@@ -31,7 +31,7 @@ public class DocToImagesOptions
         List<int> PageList = new List<int>(0);
         int evenoddpages; // 1 = all odd pages, 2 = all even pages.
         string outputfilename = "";
-        string outputdirname = "";
+        string? outputdirname = "";
         SmoothFlags smoothingflags = SmoothFlags.None;
         bool reversegray;
         bool blackisone;
@@ -214,12 +214,12 @@ public string getoutputfile()
             return (outputfilename);
         }
 
-        public void setoutputdir(string outputdir)
+        public void setoutputdir(string? outputdir)
         {
             outputdirname = outputdir;
         }
 
-        public string getoutputdir()
+        public string? getoutputdir()
         {
             return (outputdirname);
         }
@@ -1071,7 +1071,7 @@ static void Main(string[] args)
             // ReSharper disable once UnusedVariable
             using (Library lib = new Library(options.getfontdirs()))
             {
-                Document pdfdocument = null;
+                Document? pdfdocument = null;
                 int numpages = 0;
                 try
                 {
@@ -1089,7 +1089,7 @@ static void Main(string[] args)
                  * of the output filename and directory name.
                  */
 
-                string outputfilename;
+                string? outputfilename;
                 if (options.getoutputfile() == "")
                 {
                     outputfilename = docpath;
@@ -1169,7 +1169,7 @@ static void Main(string[] args)
                     i++) // Get the images of the PDF pages to create an image collection.
                 {
                     Page docpage = pdfdocument.GetPage(pagelist[i]);
-                    Rect PageRect = null;
+                    Rect? PageRect = null;
                     if (options.getpageregion().Equals("crop"))
                     {
                         PageRect = docpage.CropBox;

Images/ImageExport/ImageExport.cs

@@ -117,17 +117,17 @@ public void Export_Element_Images(Content content)
                 else if (e is Container)
                 {
                     Console.WriteLine("Recursing through a Container");
-                    Export_Element_Images((e as Container).Content);
+                    Export_Element_Images(((Container)e).Content);
                 }
                 else if (e is Group)
                 {
                     Console.WriteLine("Recursing through a Group");
-                    Export_Element_Images((e as Group).Content);
+                    Export_Element_Images(((Group)e).Content);
                 }
                 else if (e is Form)
                 {
                     Console.WriteLine("Recursing through a Form");
-                    Export_Element_Images((e as Form).Content);
+                    Export_Element_Images(((Form)e).Content);
                 }
 
                 i++;

Images/ImageExtraction/ImageExtraction.cs

@@ -47,15 +47,15 @@ static void ExtractImages(Content content)
                 }
                 else if (e is Datalogics.PDFL.Container)
                 {
-                    ExtractImages((e as Datalogics.PDFL.Container).Content);
+                    ExtractImages(((Datalogics.PDFL.Container)e).Content);
                 }
                 else if (e is Datalogics.PDFL.Group)
                 {
-                    ExtractImages((e as Datalogics.PDFL.Group).Content);
+                    ExtractImages(((Datalogics.PDFL.Group)e).Content);
                 }
                 else if (e is Form)
                 {
-                    ExtractImages((e as Form).Content);
+                    ExtractImages(((Datalogics.PDFL.Form)e).Content);
                 }
             }
         }

Images/ImageResampling/ImageResampling.cs

@@ -47,19 +47,19 @@ static void ResampleImages(Content content)
                 else if (e is Container)
                 {
                     Console.WriteLine("Recursing through a Container");
-                    ResampleImages((e as Container).Content);
+                    ResampleImages(((Container)e).Content);
                 }
                 else if (e is Group)
                 {
                     Console.WriteLine("Recursing through a Group");
-                    ResampleImages((e as Group).Content);
+                    ResampleImages(((Group)e).Content);
                 }
                 else if (e is Form)
                 {
                     Console.WriteLine("Recursing through a Form");
-                    Content formcontent = (e as Form).Content;
+                    Content formcontent = ((Form)e).Content;
                     ResampleImages(formcontent);
-                    (e as Form).Content = formcontent;
+                    ((Form)e).Content = formcontent;
                 }
 
                 i++;

InformationExtraction/ListPaths/ListPaths.cs

@@ -54,22 +54,22 @@ private static void ListPathsInContent(Content content, int pgno)
 
                 if (e is Datalogics.PDFL.Path)
                 {
-                    ListPath(e as Datalogics.PDFL.Path, pgno);
+                    ListPath((Datalogics.PDFL.Path)e, pgno);
                 }
                 else if (e is Container)
                 {
                     Console.WriteLine("Recurring through a Container");
-                    ListPathsInContent((e as Container).Content, pgno);
+                    ListPathsInContent(((Datalogics.PDFL.Container)e).Content, pgno);
                 }
                 else if (e is Group)
                 {
                     Console.WriteLine("Recurring through a Group");
-                    ListPathsInContent((e as Group).Content, pgno);
+                    ListPathsInContent(((Datalogics.PDFL.Group)e).Content, pgno);
                 }
                 else if (e is Form)
                 {
                     Console.WriteLine("Recurring through a Form");
-                    ListPathsInContent((e as Form).Content, pgno);
+                    ListPathsInContent(((Datalogics.PDFL.Form)e).Content, pgno);
                 }
             }
         }
@@ -83,40 +83,40 @@ private static void ListPath(Datalogics.PDFL.Path path, int pgno)
             {
                 if (segment is MoveTo)
                 {
-                    MoveTo moveto = segment as MoveTo;
+                    MoveTo moveto = (MoveTo)segment;
                     Console.WriteLine("  MoveTo x={0}, y={1}", moveto.Point.H, moveto.Point.V);
                 }
                 else if (segment is LineTo)
                 {
-                    LineTo lineto = segment as LineTo;
+                    LineTo lineto = (LineTo)segment;
                     Console.WriteLine("  LineTo x={0}, y={1}",
                         lineto.Point.H, lineto.Point.V);
                 }
                 else if (segment is CurveTo)
                 {
-                    CurveTo curveto = segment as CurveTo;
+                    CurveTo curveto = (CurveTo)segment;
                     Console.WriteLine("  CurveTo x1={0}, y1={1}, x2={2}, y2={3}, x3={4}, y3={5}",
                         curveto.Point1.H, curveto.Point1.V,
                         curveto.Point2.H, curveto.Point2.V,
                         curveto.Point3.H, curveto.Point3.V);
                 }
                 else if (segment is CurveToV)
                 {
-                    CurveToV curveto = segment as CurveToV;
+                    CurveToV curveto = (CurveToV)segment;
                     Console.WriteLine("  CurveToV x2={0}, y2={1}, x3={2}, y3={3}",
                         curveto.Point2.H, curveto.Point2.V,
                         curveto.Point3.H, curveto.Point3.V);
                 }
                 else if (segment is CurveToY)
                 {
-                    CurveToY curveto = segment as CurveToY;
+                    CurveToY curveto = (CurveToY)segment;
                     Console.WriteLine("  CurveToV x1={0}, y1={1}, x3={2}, y3={3}",
                         curveto.Point1.H, curveto.Point1.V,
                         curveto.Point3.H, curveto.Point3.V);
                 }
                 else if (segment is RectSegment)
                 {
-                    RectSegment rect = segment as RectSegment;
+                    RectSegment rect = (RectSegment)segment;
                     Console.WriteLine("  Rectangle x={0}, y={1}, width={2}, height={3}",
                         rect.Point.H, rect.Point.V,
                         rect.Width, rect.Height);

InformationExtraction/Metadata/Metadata.cs

@@ -75,43 +75,61 @@ private static void DisplayImageMetadata(String input)
             {
                 // Demonstrate getting data from an image
                 Content content = doc.GetPage(0).Content;
-                Container container = (Container) content.GetElement(0);
-                Datalogics.PDFL.Image image = (Datalogics.PDFL.Image) container.Content.GetElement(0);
+                Container container = (Container)content.GetElement(0);
+                Datalogics.PDFL.Image image = (Datalogics.PDFL.Image)container.Content.GetElement(0);
                 String metadata = image.Stream.Dict.XMPMetadata;
                 Console.WriteLine("Ducky CreatorTool: {0}\n", GetCreatorToolAttribute(metadata));
             }
         }
 
         static string GetTitle(string xmlstring)
         {
+            string title = "";
+
             XmlDocument xmldoc = new XmlDocument();
             xmldoc.LoadXml(xmlstring);
-            XmlElement element = (XmlElement) xmldoc.GetElementsByTagName("dc:title")[0];
-            XmlNode titleNode = element.GetElementsByTagName("rdf:li")[0];
-            return GetText(titleNode.ChildNodes);
+            XmlElement? element = (XmlElement?)xmldoc.GetElementsByTagName("dc:title")[0];
+            if (element != null)
+            {
+                XmlNode? titleNode = element.GetElementsByTagName("rdf:li")[0];
+                if (titleNode != null)
+                {
+                    title = GetText(titleNode.ChildNodes);
+                }
+            }
+
+            return title;
         }
 
         // ReSharper disable once UnusedMember.Local
         static string GetCreatorTool(string xmlstring)
         {
+            string creatorTool = "";
             XmlDocument xmldoc = new XmlDocument();
             xmldoc.LoadXml(xmlstring);
-            XmlElement element = (XmlElement) xmldoc.GetElementsByTagName("xap:CreatorTool")[0];
-            return GetText(element.ChildNodes);
+            XmlElement? element = (XmlElement?)xmldoc.GetElementsByTagName("xap:CreatorTool")[0];
+            if (element != null)
+            {
+                creatorTool = GetText(element.ChildNodes);
+            }
+
+            return creatorTool;
         }
 
         static string GetCreatorToolAttribute(string xmlstring)
         {
+            string creatorToolAttribute = "";
+
             XmlDocument xmldoc = new XmlDocument();
             xmldoc.LoadXml(xmlstring);
             foreach (XmlNode node in xmldoc.GetElementsByTagName("rdf:Description"))
             {
                 XmlElement e = (XmlElement) node;
                 if (e.HasAttribute("xap:CreatorTool"))
-                    return e.GetAttribute("xap:CreatorTool");
+                    creatorToolAttribute = e.GetAttribute("xap:CreatorTool");
             }
 
-            return null;
+            return creatorToolAttribute;
         }
 
         static string GetText(XmlNodeList nodeList)

OpticalCharacterRecognition/AddTextToDocument/AddTextToDocument.cs

@@ -32,15 +32,15 @@ static void AddTextToImages(Document doc, Content content, OCREngine engine)
                 }
                 else if (e is Container)
                 {
-                    AddTextToImages(doc, (e as Container).Content, engine);
+                    AddTextToImages(doc, ((Container)e).Content, engine);
                 }
                 else if (e is Group)
                 {
-                    AddTextToImages(doc, (e as Group).Content, engine);
+                    AddTextToImages(doc, ((Group)e).Content, engine);
                 }
                 else if (e is Form)
                 {
-                    AddTextToImages(doc, (e as Form).Content, engine);
+                    AddTextToImages(doc, ((Form)e).Content, engine);
                 }
             }
         }

Text/AddUnicodeText/AddUnicodeText.cs

@@ -88,7 +88,7 @@ static void Main(string[] args)
                 foreach (String str in strings)
                 {
                     // Find a font that can represent all characters in the string, if there is one.
-                    Font font = GetRepresentableFont(fonts, str);
+                    Font? font = GetRepresentableFont(fonts, str);
                     if (font == null)
                     {
                         Console.WriteLine(
@@ -117,7 +117,7 @@ static void Main(string[] args)
             }
         }
 
-        static Font GetRepresentableFont(List<Font> fonts, String str)
+        static Font? GetRepresentableFont(List<Font> fonts, String str)
         {
             foreach (Font font in fonts)
             {