added null value handle for image resizer size input (#4721)

* addle null value handle for image resizer size input

* check for negative withd and height

* check for negative withd and height

* Update ImageSize.cs

Co-authored-by: Lavius Motileng <laviusntk>

src/core/Microsoft.PowerToys.Settings.UI.Lib/ImageSize.cs

@@ -144,9 +144,17 @@ namespace Microsoft.PowerToys.Settings.UI.Lib
 
             set
             {
+                int newWidth = -1;
+                int.TryParse(value + string.Empty, out newWidth);
+
+                if (newWidth < 0)
+                {
+                    newWidth = 0;
+                }
+
                 if (_width != value)
                 {
-                    _width = value;
+                    _width = newWidth;
                     OnPropertyChanged();
                 }
             }
@@ -162,9 +170,17 @@ namespace Microsoft.PowerToys.Settings.UI.Lib
 
             set
             {
+                int newHeight = -1;
+                int.TryParse(value + string.Empty, out newHeight);
+
+                if (newHeight < 0)
+                {
+                    newHeight = 0;
+                }
+
                 if (_height != value)
                 {
-                    _height = value;
+                    _height = newHeight;
                     OnPropertyChanged();
                 }
             }

src/core/Microsoft.PowerToys.Settings.UnitTest/ViewModelTests/ImageResizer.cs

@@ -183,5 +183,39 @@ namespace ViewModelTests
             Assert.AreEqual(viewModel.Sizes.Count, sizeOfOriginalArray - 1);
             Assert.IsFalse(viewModel.Sizes.Contains(deleteCandidate));
         }
+
+        [TestMethod]
+        public void UpdateWidthAndHeight_ShouldUpateSize_WhenCorrectValuesAreProvided()
+        {
+            // arrange
+            ImageSize imageSize = new ImageSize()
+            {
+                Id = 0,
+                Name = "Test",
+                Fit = (int)ResizeFit.Fit,
+                Width = 30,
+                Height = 30,
+                Unit = (int)ResizeUnit.Pixel,
+            };
+
+            double negativeWidth = -2.0;
+            double negativeHeight = -2.0;
+
+            // Act 
+            imageSize.Width = negativeWidth;
+            imageSize.Height = negativeHeight;
+
+            // Assert
+            Assert.AreEqual(0, imageSize.Width);
+            Assert.AreEqual(0, imageSize.Height);
+
+            // Act 
+            imageSize.Width = 50;
+            imageSize.Height = 50;
+
+            // Assert
+            Assert.AreEqual(50, imageSize.Width);
+            Assert.AreEqual(50, imageSize.Height);
+        }
     }
 }