post抓包格式问题

下面是抓回来的格式，像text_number这种可以写成text_number=&_file9385a6=这样的格式
那像file_number和file0这句该怎么用&连成字符串呢,写成file_number=&text_number=&_file9385a6=这样的话会返回500错误，说是无效的过程调用或参数: 'MidB'
-----------------------------14149489422628
 Content-Disposition: form-data; name="file_number"; filename="" Content-Type: application/octet-stream 
-----------------------------14149489422628
 Content-Disposition: form-data; name="text_number" 

-----------------------------14149489422628
 Content-Disposition: form-data; name="_file9385a6" 

-----------------------------14149489422628 
Content-Disposition: form-data; name="file0"; filename="" Content-Type: application/octet-stream 
-----------------------------14149489422628
 Content-Disposition: form-data; name="text0"

 -----------------------------14149489422628 
Content-Disposition: form-data; name="Form_TopicType" 
0 
-----------------------------14149489422628
 Content-Disposition: form-data; name="Form_NeedValue" 

-----------------------------14149489422628 
Content-Disposition: form-data; name="Form_NoUserUnderWriteFlag"
 checkbox 
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补充：.NET技术 ,  VB.NET