Address feedback

src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/MouseDevice.cs

@@ -1195,7 +1195,7 @@ private void PreProcessInput(object sender, PreProcessInputEventArgs e)
                         }
                     }
                     // Only process mouse input that is from our active PresentationSource.
-                    else if ((_inputSource != null) && (rawMouseInputReport.InputSource == _inputSource))
+                    else if ((_inputSource is not null) && (rawMouseInputReport.InputSource == _inputSource))
                     {
                         // We need to remember the StylusDevice that generated this input.  Use the _tagStylusDevice
                         // to store this in before we take over the inputReport Device and loose it.  Any
@@ -1440,7 +1440,7 @@ private void PreNotifyInput(object sender, NotifyInputEventArgs e)
                     }
 
                     // Only process mouse input that is from our active presentation source.
-                    if ((_inputSource != null) && (rawMouseInputReport.InputSource == _inputSource))
+                    if ((_inputSource is not null) && (rawMouseInputReport.InputSource == _inputSource))
                     {
                         // If the input is reporting mouse deactivation, we need
                         // to break any capture we may have.  Note that we only do
@@ -1888,7 +1888,7 @@ private void PostProcessInput(object sender, ProcessInputEventArgs e)
                     RawMouseInputReport rawMouseInputReport = (RawMouseInputReport) inputReportEventArgs.Report;
 
                     // Only process mouse input that is from our active visual manager.
-                    if ((_inputSource != null) && (rawMouseInputReport.InputSource == _inputSource))
+                    if ((_inputSource is not null) && (rawMouseInputReport.InputSource == _inputSource))
                     {
                         // In general, this is where we promote the non-redundant
                         // reported actions to our premier events.

src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Wisp/PenThreadWorker.cs

@@ -208,7 +208,7 @@ protected override void OnDoWork()
                     // so that nothing gets lost during marshalling. The cast from Int64 to Int32 below
                     // should be lossless cast because both COM server and client are expected
                     // to be of same bitness (they are in the same process).
-                    result.CommHandle = IntPtr.Size == 4 ? new IntPtr((int)commHandle) : new IntPtr(commHandle);
+                    result.CommHandle = Environment.Is64BitProcess ? (nint)commHandle : (int)commHandle;
 
                     result.WispContextKey = MS.Win32.Penimc.UnsafeNativeMethods.QueryWispContextKey(pimcContext);
 

src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/InterOp/HwndMouseInputProvider.cs

@@ -780,7 +780,7 @@ internal IntPtr FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, Int
                     // to this we release capture if we currently have it.
                     try
                     {
-                        if(_source.HasCapture )
+                        if(_source.HasCapture)
                         {
                             SafeNativeMethods.ReleaseCapture();
                         }

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Documents/TextServicesHost.cs

@@ -328,7 +328,7 @@ private void _RegisterTextStore(TextStore textstore)
 
             // Create a TSF document.
             _threadManager.CreateDocumentMgr(out doc);
-            doc.CreateContext(_clientId, 0 /* flags */, textstore, out context, out editCookie);
+            doc.CreateContext(_clientId, flags: 0, textstore, out context, out editCookie);
             doc.Push(context);
 
             // Attach a thread focus sink.

src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/Threading/Dispatcher.cs

@@ -2409,14 +2409,7 @@ internal bool CriticalRequestProcessing(bool force)
             return succeeded;
         }
 
-        private bool IsWindowNull()
-        {
-           if(_window == null)
-            {
-                return true;
-            }
-            return false;
-        }
+        private bool IsWindowNull() => _window is null;
 
         private bool RequestForegroundProcessing()
         {