diff --git a/api/core/handlers/handlers.go b/api/core/handlers/handlers.go
index 1bc50788..adf78839 100644
--- a/api/core/handlers/handlers.go
+++ b/api/core/handlers/handlers.go
@@ -365,24 +365,22 @@ func reqBodyFromFormData(_ *core.Context, req *request.Request) {
 	}
 	writer := multipart.NewWriter(reqBody)
 	for key, val := range fd.Params() {
-		switch v := val.(type) {
-		case *request.File:
-			part, err := writer.CreatePart(v.MIMEHeader())
-			if err != nil {
-				req.Err = err
-				return
-			}
-			_, err = io.Copy(part, v)
-			if err != nil {
-				req.Err = err
-				return
-			}
-		default:
-			err := writer.WriteField(key, fmt.Sprint(val))
-			if err != nil {
-				req.Err = err
-				return
-			}
+		err := writer.WriteField(key, fmt.Sprint(val))
+		if err != nil {
+			req.Err = err
+			return
+		}
+	}
+	for _, file := range fd.Files() {
+		part, err := writer.CreatePart(file.MIMEHeader())
+		if err != nil {
+			req.Err = err
+			return
+		}
+		_, err = io.Copy(part, file)
+		if err != nil {
+			req.Err = err
+			return
 		}
 	}
 	req.ContentType = writer.FormDataContentType()
diff --git a/api/core/request/formdata.go b/api/core/request/formdata.go
index ddf73eaf..667688b6 100644
--- a/api/core/request/formdata.go
+++ b/api/core/request/formdata.go
@@ -17,6 +17,10 @@ func (fd *FormData) Params() map[string]interface{} {
 	return fd.params
 }
 
+func (fd *FormData) Files() []*File {
+	return fd.files
+}
+
 func NewFormData() *FormData {
 	return &FormData{
 		params: map[string]interface{}{},
@@ -29,7 +33,6 @@ func (fd *FormData) AddParam(field string, val interface{}) *FormData {
 }
 
 func (fd *FormData) AddFile(field string, file *File) *FormData {
-	fd.params[field] = file
 	file.fieldName = field
 	fd.files = append(fd.files, file)
 	return fd