public void TestUpdateRange() { var before = ObjectContent_Before.Substring(0, ObjectContent_Before.IndexOf(ObjectContent_Replace_Old)); var updateRequest = (UpdateObjectRequest) new UpdateObjectRequest() .WithUpdateRange( Encoding.UTF8.GetByteCount(before), Encoding.UTF8.GetByteCount(before) + Encoding.UTF8.GetByteCount(ObjectContent_Replace_New) - 1) .WithBucketName(bucket.BucketName) .WithKey(this.objKey) .WithContentBody(ObjectContent_Replace_New); using (var updateResponse = client.UpdateObject(updateRequest)) { } // check content var getRequest = new GetObjectRequest() .WithBucketName(bucket.BucketName) .WithKey(this.objKey); using (var getResponse = client.GetObject(getRequest)) { string contentBody = getResponse.GetResponseContentBody(); Assert.AreEqual(ObjectContent_After, contentBody); } }