diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1640,8 +1640,9 @@
 
   /// Determine whether ')' is ending a cast.
   bool rParenEndsCast(const FormatToken &Tok) {
-    // C-style casts are only used in C++ and Java.
-    if (!Style.isCpp() && Style.Language != FormatStyle::LK_Java)
+    // C-style casts are only used in C++, C# and Java.
+    if (!Style.isCSharp() && !Style.isCpp() &&
+        Style.Language != FormatStyle::LK_Java)
       return false;
 
     // Empty parens aren't casts and there are no casts at the end of the line.
diff --git a/clang/unittests/Format/FormatTestCSharp.cpp b/clang/unittests/Format/FormatTestCSharp.cpp
--- a/clang/unittests/Format/FormatTestCSharp.cpp
+++ b/clang/unittests/Format/FormatTestCSharp.cpp
@@ -374,5 +374,14 @@
                Style);
 }
 
+TEST_F(FormatTestCSharp, CSharpSpaceAfterCStyleCast) {
+  FormatStyle Style = getGoogleStyle(FormatStyle::LK_CSharp);
+
+  verifyFormat("(int)x / y;", Style);
+
+  Style.SpaceAfterCStyleCast = true;
+  verifyFormat("(int) x / y;", Style);
+}
+
 } // namespace format
 } // end namespace clang