Fixing some NPR Exceptions.

Greenshot/Drawing/CropContainer.cs

@@ -50,24 +50,20 @@ namespace Greenshot.Drawing {
 		}
 
 		public override void Invalidate() {
-			if (_parent == null)
+			_parent?.Invalidate();
-			{
-				return;
-			}
-			_parent.Invalidate();
 		}
 
 		/// <summary>
 		/// We need to override the DrawingBound, return a rectangle in the size of the image, to make sure this element is always draw
 		/// (we create a transparent brown over the complete picture)
 		/// </summary>
-		public override Rectangle DrawingBounds {
+		public override Rectangle DrawingBounds => new Rectangle(0,0,_parent?.Width??0, _parent?.Height ?? 0);
-			get {
-				return new Rectangle(0,0,_parent.Width, _parent.Height);
-			}
-		}
 
 		public override void Draw(Graphics g, RenderMode rm) {
+			if (_parent == null)
+			{
+				return;
+			}
 			using (Brush cropBrush = new SolidBrush(Color.FromArgb(100, 150, 150, 100))) {
 				Rectangle cropRectangle = GuiRectangle.GetGuiRectangle(Left, Top, Width, Height);
 				Rectangle selectionRect = new Rectangle(cropRectangle.Left - 1, cropRectangle.Top - 1, cropRectangle.Width + 1, cropRectangle.Height + 1);

Greenshot/Drawing/DrawableContainer.cs

@@ -89,14 +89,7 @@ namespace Greenshot.Drawing
 			if (!disposing) {
 				return;
 			}
-			if (_parent != null)
+			_parent?.FieldAggregator?.UnbindElement(this);
-			{
-				FieldAggregator fieldAggregator = _parent.FieldAggregator;
-				if (fieldAggregator != null)
-				{
-					fieldAggregator.UnbindElement(this);
-				}
-			}
 		}
 
 		~DrawableContainer() {
@@ -306,7 +299,7 @@ namespace Greenshot.Drawing
 
 		public virtual void Invalidate() {
 			if (Status != EditStatus.UNDRAWN) {
-				_parent.Invalidate(DrawingBounds);
+				_parent?.Invalidate(DrawingBounds);
 			}
 		}
 		
@@ -491,15 +484,7 @@ namespace Greenshot.Drawing
 			{
 				return;
 			}
-			if (_parent != null)
+			_parent.FieldAggregator?.UnbindElement(this);
-			{
-				// Remove FieldAggregator
-				FieldAggregator fieldAggregator = _parent.FieldAggregator;
-				if (fieldAggregator != null)
-				{
-					fieldAggregator.UnbindElement(this);
-				}
-			}
 
 			_parent = newParent;
 			foreach(IFilter filter in Filters) {
@@ -521,7 +506,7 @@ namespace Greenshot.Drawing
 		/// <param name="fieldToBeChanged">The field to be changed</param>
 		/// <param name="newValue">The new value</param>
 		public virtual void BeforeFieldChange(IField fieldToBeChanged, object newValue) {
-			_parent.MakeUndoable(new ChangeFieldHolderMemento(this, fieldToBeChanged), true);
+			_parent?.MakeUndoable(new ChangeFieldHolderMemento(this, fieldToBeChanged), true);
 			Invalidate();
 		}
 		

Greenshot/Drawing/FreehandContainer.cs

@@ -217,7 +217,7 @@ namespace Greenshot.Drawing {
 					int safetymargin = 10;
 					return new Rectangle(myBounds.Left + Left - (safetymargin+lineThickness), myBounds.Top + Top - (safetymargin+lineThickness), myBounds.Width + 2*(lineThickness+safetymargin), myBounds.Height + 2*(lineThickness+safetymargin));
 				}
-				return new Rectangle(0, 0, _parent.Width, _parent.Height);
+				return new Rectangle(0, 0, _parent?.Width??0, _parent?.Height?? 0);
 			}
 		}
 

Greenshot/Drawing/TextContainer.cs

@@ -40,14 +40,12 @@ namespace Greenshot.Drawing {
 	public class TextContainer : RectangleContainer, ITextContainer {
 		// If makeUndoable is true the next text-change will make the change undoable.
 		// This is set to true AFTER the first change is made, as there is already a "add element" on the undo stack
+		// Although the name is wrong, we can't change it due to file serialization
+		// ReSharper disable once InconsistentNaming
 		private bool makeUndoable;
 		[NonSerialized]
 		private Font _font;
-		public Font Font {
+		public Font Font => _font;
-			get {
-				return _font;
-			}
-		}
 
 		[NonSerialized]
 		private TextBox _textBox;
@@ -57,11 +55,10 @@ namespace Greenshot.Drawing {
 		/// </summary>
 		[NonSerialized]
 		StringFormat _stringFormat = new StringFormat();
-		public StringFormat StringFormat {
+		public StringFormat StringFormat => _stringFormat;
-			get {
+
-				return _stringFormat;
+		// Although the name is wrong, we can't change it due to file serialization
-			}
+		// ReSharper disable once InconsistentNaming
-		}
 		private string text;
 		// there is a binding on the following property!
 		public string Text {
@@ -168,7 +165,7 @@ namespace Greenshot.Drawing {
 					HideTextBox();
 				} else if (Selected && Status == EditStatus.DRAWING) {
 					ShowTextBox();
-				} else if (Selected && Status == EditStatus.IDLE && _textBox.Visible) {
+				} else if (_parent != null && Selected && Status == EditStatus.IDLE && _textBox.Visible) {
 					// Fix (workaround) for BUG-1698
 					_parent.KeysLocked = true;
 				}
@@ -221,8 +218,11 @@ namespace Greenshot.Drawing {
 		}
 
 		private void ShowTextBox() {
-			_parent.KeysLocked = true;
+			if (_parent != null)
-			_parent.Controls.Add(_textBox);
+			{
+				_parent.KeysLocked = true;
+				_parent.Controls.Add(_textBox);
+			}
 			EnsureTextBoxContrast();
 			_textBox.Show();
 			_textBox.Focus();