added IRestRequest AddFile(string name, string path, string contentType)

now it's possible to upload a file with a correct content-type

Author: cecil

RestSharp/IRestRequest.cs

@@ -139,6 +139,16 @@ public interface IRestRequest
         /// <returns>This request</returns>
         IRestRequest AddFile(string name, string path);
 
+        /// <summary>
+        /// Adds a file to the Files collection to be included with a POST or PUT request with the specified content type
+        /// (other methods do not support file uploads).
+        /// </summary>
+        /// <param name="name">The parameter name to use in the request</param>
+        /// <param name="path">Full path to file to upload</param>
+        /// <param name="contentType">The MIME type of the file to upload</param>
+        /// <returns>This request</returns>
+        IRestRequest AddFile(string name, string path, string contentType);
+
         /// <summary>
         /// Adds the bytes to the Files collection with the specified file name
         /// </summary>

RestSharp/RestRequest.cs

@@ -141,6 +141,35 @@ public IRestRequest AddFile(string name, string path)
                            });
         }
 
+        /// <summary>
+        /// Adds a file to the Files collection to be included with a POST or PUT request with the specified content type
+        /// (other methods do not support file uploads).
+        /// </summary>
+        /// <param name="name">The parameter name to use in the request</param>
+        /// <param name="path">Full path to file to upload</param>
+        /// <param name="contentType">The MIME type of the file to upload</param>
+        /// <returns>This request</returns>
+        public IRestRequest AddFile(string name, string path, string contentType)
+        {
+            FileInfo f = new FileInfo(path);
+            long fileLength = f.Length;
+
+            return AddFile(new FileParameter
+            {
+                Name = name,
+                FileName = Path.GetFileName(path),
+                ContentLength = fileLength,
+                Writer = s =>
+                {
+                    using (var file = new StreamReader(path))
+                    {
+                        file.BaseStream.CopyTo(s);
+                    }
+                },
+                ContentType = contentType
+            });
+        }
+
         /// <summary>
         /// Adds the bytes to the Files collection with the specified file name
         /// </summary>