diff --git a/lib/csharp/src/Protocol/TJSONProtocol.cs b/lib/csharp/src/Protocol/TJSONProtocol.cs
index 7c88f0f..5f6351f 100644
--- a/lib/csharp/src/Protocol/TJSONProtocol.cs
+++ b/lib/csharp/src/Protocol/TJSONProtocol.cs
@@ -744,7 +744,7 @@
 					}
 					else
 					{
-						int off = Array.IndexOf(ESCAPE_CHARS, ch);
+						int off = Array.IndexOf(ESCAPE_CHARS, (char)ch);
 						if (off == -1)
 						{
 							throw new TProtocolException(TProtocolException.INVALID_DATA,