4.23Setting the Operation Before Adding Form Item Content

Created on Aug 17, 2026~1 min read

Before adding a HttpContent instance to a MultipartFormDataContent object, you can perform some preprocessing operations. For example, when integrating with certain object storage services (such as Alibaba Cloud OSS), you may need to remove the Content-Type setting (the framework has built in this operation).

cs
HttpRequestBuilder.Post("https://furion.net")    .SetMultipartContent(multipart =>    {        multipart.SetBoundary("--------------------------")            .AddFormItem("1", "id")            .AddFormItem("Furion", "name")            .SetOnPreAddContent((content, name) => // The delegate parameter type is: Action<HttpContent, string>            {                content.Headers.ContentType = null;            });    });

Note: The SetOnPreAddContent method supports being called multiple times; the results of each call accumulate.