使用HttpClient接入

普通用户请忽略本节内容，除非你想了解LLMCaller的底层原理。

LLMCaller是基于HttpClient封装的，有关HttpClient请参考：HttpClient简介

你可以通过HttpClient直接用最原生的方式访问大模型的API接口，下面我们给出一些简单的示例，这些示例对普通用户来说还是太复杂，且很难保证质量，所以除非有特别情况，一般使用LLMCaller接入即可。

基础接入

Dim hc As New HttpClient("https://api.deepseek.com/chat/completions")
hc.SkipError = True
hc.ContentType = "application/json" '必须设置
hc.Headers.Add("Authorization", "Bearer sk-a734b83536da45e9aedc3e42605bfb3a")  '记得替换为自己的密钥哦
'构造请求体，JSON格式：
hc.Content = <![CDATA[
{
  "model": "deepseek-flash",
  "messages": [
    {"role": "system", "content": "你是唐朝诗人李白"},
    {"role": "user", "content": "请写一首睹月思人的情诗"}
  ],
  "thinking": {"type": "enabled"},
  "reasoning_effort": "high",
  "stream": false
}
]]>.Value
Dim res As String = hc.GetData()
If hc.StatusCode = 200 Then
    Dim resp As JObject = JsonConvert.DeserializeObject(res)
    Dim answer As String = resp("choices")(0)("message")("content").ToString()
    MessageBoxA.Show("AI回答：" & vbCrLf & answer)
Else
    MessageBoxA.Show("请求失败，状态码：" & hc.StatusCode & vbCrLf & "状态描述：" & hc.StatusDescription)
End If 　

使用流输出

构造请求JSON时，如果将stream字段设置为true，大模型接口会启用 SSE 流式分片返回数据；若为false则一次性返回全部数据。

HttpClient有一个ReadOpenAiSseAsync方法，专门用于接收大模型的API接口按SSE流格式输出的分片内容。

ReadOpenAiSseAsync方法是异步的，需要配合Await关键词使用：

Dim res As JObject = Await hc.ReadOpenAiSseAsync(chunkHandler)

chunkHandler：用于处理分片数据的回调函数，类型为：Action(Of String, String)

ReadOpenAiSseAsync每收到一个分片数据，都会调用chunkHandler参数指定的回调函数进行处理，同时会将所有分片数据拼接在一起，在函数执行结束后返回 。

这个回调函数的类型为Action(Of String, String)，包括两个String型参数：

内容类型有三种：

• think：大模型深度思考 / 推理片段；
  　
• answer：大模型正式回复文本片段；
  　
• error：网络、解析、HTTP 请求过程中产生的错误信息，正常无异常时为空

需要注意的是，不管是否指定回调函数，ReadOpenAiSseAsync都会正常返回全部数据，回调函数作用通常仅限于刷新界面，实现打字效果，而不是获取数据。

以下代码可以在命令窗口测试执行，

'''Async
'定义三个StringBuilder用于接收不同类型的数据片段，实际开发的时候可以将StringBuilder替换为显示内容的控件
Dim answers As New StringBuilder()
Dim thinks As New StringBuilder()
Dim errors As New StringBuilder()
'定义一个函数用于接收流式输出内容，这里按内容类型分别存储在三个StringBuilder中
Dim chunkHandler As Action(Of String, String) =
Sub(ttype As String, tcontent As String)
    Select Case ttype
        Case "think"
            thinks.Append(tcontent)
        Case "answer"
            answers.Append(tcontent)
        Case "error"
            errors.Append(tcontent)
    End Select
End Sub
'发起访问
Dim hc As New HttpClient("https://api.deepseek.com/chat/completions")
hc.ContentType = "application/json" '必须设置
hc.Headers.Add("Authorization", "Bearer sk-a734b83536da45e9aedc3e42605bfb3a") '替换为自己的密钥哦
'构造请求体，JSON格式：
hc.Content = <![CDATA[
{
  "model": "deepseek-flash",
  "messages": [
    {"role": "system", "content": "你是一个唐朝诗人"},
    {"role": "user", "content": "请写一首睹月思人的情诗"}
  ],
  "stream": true 
}
]]>.Value
Dim retJO As JObject = Await hc.ReadOpenAiSseAsync(chunkHandler) '指定用于接收片段内容的回调函数
If retJO.ContainsKey("error") Then
    MessageBoxA.Show(retJO("error").ToString(), "请求失败")
Else
    Dim answer = retJO("choices")(0)("message")("content").ToString()
    Output.Show("正常答案：" & vbCrLf & answer) '即使指定了回调函数，ReadOpenAiSseAsync还是会正常返回全部数据
    '显示一下通过片段内容拼接起来的结果
    Output.Show("拼接的推理过程：" & vbCrLf & thinks.ToString())
    Output.Show("拼接的答案：" & vbCrLf & answers.ToString())
    MessageBoxA.Show("测试完毕")
End If

使用Files API

'''Async
' ---- 第1步：上传图片，获取 file_id ----
Dim imgPath As String = "C:\test\test.jpg" '本地图片文件
Dim apiKey As String = "sk-a734b83536da45e9aedc3e42605bfb3a" '请替换为自己的密钥
Dim uploadHc As New HttpClient("https://api.deepseek.com/files")
uploadHc.SkipError = True
uploadHc.Headers.Add("Authorization", "Bearer " & apiKey)
uploadHc.FormData.Add("purpose", "user_data")
uploadHc.Files.Add("file", imgPath)
Dim uploadRes As String = Await uploadHc.GetDataAsync()
If uploadHc.StatusCode <> 200 Then
    MessageBoxA.Show("文件上传失败：" & vbCrLf &
        "状态码：" & uploadHc.StatusCode & vbCrLf &
        "状态描述：" & uploadHc.StatusDescription)
    Return ""
End If
Dim uploadJO As JObject = JsonConvert.DeserializeObject(uploadRes)
Dim fileId As String = uploadJO("id").ToString()
' ---- 第2步：构造聊天请求体，引用刚上传的图片 ----
Dim jo As New JObject
jo("model") = "deepseek-flash"
Dim msgArray As New JArray
msgArray.Add(New JObject From {
    {"type", "text"},
    {"text", "这张图片里有什么？"}
})
msgArray.Add(New JObject From {
    {"type", "file"},
    {"file_id", fileId}
})
Dim userMsg As New JObject
userMsg("role") = "user"
userMsg("content") = msgArray
Dim messages As New JArray
messages.Add(userMsg)
jo("messages") = messages
' ---- 第3步：发送聊天请求 ----
Dim chatHc As New HttpClient("https://api.deepseek.com/chat/completions")
chatHc.SkipError = True
chatHc.ContentType = "application/json"
chatHc.Headers.Add("Authorization", "Bearer " & apiKey)
chatHc.Content = jo.ToString()
Dim chatRes As String = Await chatHc.GetDataAsync()
If chatHc.StatusCode <> 200 Then
    MessageBoxA.Show("请求失败：" & vbCrLf &
        "状态码：" & chatHc.StatusCode & vbCrLf &
        "状态描述：" & chatHc.StatusDescription)
    Return ""
End If
Dim resp As JObject = JsonConvert.DeserializeObject(chatRes)
Dim answer As String = resp("choices")(0)("message")("content").ToString()
MessageBoxA.Show("AI回答：" & vbCrLf & answer)

多轮对话

Dim apiKey As String = "sk-a734b83536da45e9aedc3e42605bfb3a" ' 请替换为你的真实密钥
Dim msgs As New JArray '消息数组，用于存储前n-1轮用户问题和答案，以及第n轮问题
Dim jo As New JObject  '请求体

'设置AI模型
jo("model") = "deepseek-flash"
jo("messages") = msgs '将消息数组添加到请求体
'设置AI角色
Dim msg As New JObject()
msg("role") = "system"
msg("content") = "你是一个地理专家"
msgs.Add(msg) '将AI角色设置信息添加的消息数组

' ---- 第一轮 ----
msg = New JObject()
msg("role") = "user"
msg("content") = "珠穆朗玛峰有多高？"
msgs.Add(msg) '添加第一轮用户问题到消息数组
' 发起第一轮访问请求
Dim hc As New HttpClient("https://api.deepseek.com/chat/completions")
hc.ContentType = "application/json"
hc.Headers.Add("Authorization", "Bearer " & apiKey)
hc.Content = jo.ToString()
hc.SkipError = True
'获取第一轮结果
Dim res As String = hc.GetData()
If hc.StatusCode <> 200 Then
    MessageBoxA.Show("第一轮失败，状态码：" & hc.StatusCode & vbCrLf & "状态描述：" & hc.StatusDescription)
    Return ""
End If
Dim retjo As JObject = JsonConvert.DeserializeObject(res)
Dim retmsg As JObject = retjo("choices")(0)("message")
Output.Show("第一轮答案" & vbCrLf & retmsg("content").ToString())

' 在第二轮开始前，必须将第一轮的答案追加到messages数组！！！
Dim answerJO As New JObject()
answerJO("role") = "assistant"
answerJO("content") = retmsg("content")
'answerJO("reasoning_content") = retmsg("reasoning_content") '需要传递推理过程到下一轮时可取消屏蔽这行代码
msgs.Add(answerJO) '添加第一轮答案到消息数组

' ---- 第二轮 ----
msg = New JObject()
msg("role") = "user"
msg("content") = "第二高的呢？"
msgs.Add(msg) '添加第二轮用户问题到消息数组
jo("messages") = msgs
' 发起第二轮访问请求
hc = hc.Clone() 'Foxtable的HttpClient不能复用，需要克隆，克隆后修改变化的属性即可
hc.Content = jo.ToString()
res = hc.GetData()
'获取第二轮结果
If hc.StatusCode <> 200 Then
    MessageBoxA.Show("第二轮失败，状态码：" & hc.StatusCode & vbCrLf & "状态描述：" & hc.StatusDescription)
    Return ""
End If
retjo = JsonConvert.DeserializeObject(res)
retmsg = retjo("choices")(0)("message")
Output.Show("第二轮答案" & vbCrLf & retmsg("content").ToString())

工具定义与调用

Dim apiKey As String = "sk-a734b83536da45e9aedc3e42605bfb3a" '请替换为自己的密钥
' ---- 第1步：定义两个工具 ----
Dim toolsJson As String = <![CDATA[
[
  {
    "type": "function",
    "function": {
      "name": "add",
      "description": "计算两个数字的和（加法）",
      "parameters": {
        "type": "object",
        "properties": {
          "a": {"type": "number", "description": "第一个数字"},
          "b": {"type": "number", "description": "第二个数字"}
        },
        "required": ["a", "b"]
      }
    }
  },
  {
    "type": "function",
    "function": {
      "name": "subtract",
      "description": "计算两个数字的差（减法），结果为 a - b",
      "parameters": {
        "type": "object",
        "properties": {
          "a": {"type": "number", "description": "被减数"},
          "b": {"type": "number", "description": "减数"}
        },
        "required": ["a", "b"]
      }
    }
  }
]
]]>.Value
Dim tools As JArray = JsonConvert.DeserializeObject(toolsJson)
Dim jo As New JObject '请求体
Dim messages As New JArray '消息数组
' ---- 第2步：初始化请求 ----
Dim sysJO As New JObject()
sysJO("role") = "system"
sysJO("content") = "你是一个好助手，对于使用外部工具返回的结果，不得质疑篡改，无论结果对错，都直接使用即可，对于无法使用外部工具解决的问题，请依靠你的知识回复"
messages.Add(sysJO) '将系统角色添加到消息数组
Dim userMsg As New JObject '用户问题
userMsg("role") = "user"
userMsg("content") = "3 加 5 等于多少？然后 减 4 呢？"
messages.Add(userMsg) '将用户问题加入消息数组
'设置模型
jo("model") = "deepseek-flash"
jo("messages") = messages '将消息数组添加到请求体
jo("tools") = tools '将工具添加到请求体
'准备HttpClient
Dim hc As New HttpClient("https://api.deepseek.com/chat/completions")
hc.SkipError = True
hc.ContentType = "application/json"
hc.Headers.Add("Authorization", "Bearer " & apiKey)
hc.Content = jo.ToString()
' ---- 第3步：循环发起请求和执行工具调用 ----
Dim maxStep As Integer = 10 '工具调用最大步数，这里允许最多10步
Dim cnt As Integer = 0
Do While True
    cnt = cnt + 1
    If cnt > maxStep Then
        MessageBoxA.Show("工具调用最多允许10步!", "请求失败")
        Return ""
    End If
    Dim res As String = hc.GetData()
    If hc.StatusCode <> 200 Then
        MessageBoxA.Show("状态码：" & hc.StatusCode & vbCrLf & "状态描述：" & hc.StatusDescription, "请求失败")
        Return ""
    End If
    Dim resp As JObject = JsonConvert.DeserializeObject(res)
    Dim msg As JObject = resp("choices")(0)("message")
    ' 检查是否有工具调用
    If msg.ContainsKey("tool_calls") = False OrElse msg("tool_calls").Count = 0 Then
        MessageBoxA.Show("最终答案：" & vbCrLf & msg("content").ToString())' 没有工具调用，输出最终答案后返回
        Exit Do
    End If
    '有工具调用，则将消息加入消息数组
    messages.Add(msg)
    ' 执行所有工具调用
    For Each toolCall As JObject In msg("tool_calls")
        Dim toolName As String = toolCall("function")("name").ToString()
        Dim callId As String = toolCall("id").ToString()
        Dim arguments As String = toolCall("function")("arguments").ToString()
        Dim argsObj As JObject = JsonConvert.DeserializeObject(arguments)
        Dim result As String = ""
        Select Case toolName
            Case "add"
                Dim a As Double = argsObj("a").ToObject(Of Double)()
                Dim b As Double = argsObj("b").ToObject(Of Double)()
                result = (a * 10 + b * 10).ToString()
            Case "subtract"
                Dim a As Double = argsObj("a").ToObject(Of Double)()
                Dim b As Double = argsObj("b").ToObject(Of Double)()
                result = (a * 10 - b * 10).ToString()
            Case Else
                result = "未知工具：" & toolName
        End Select
        ' 构造工具结果消息
        Dim toolMsg As New JObject
        toolMsg("role") = "tool"
        toolMsg("tool_call_id") = callId
        toolMsg("content") = result
        messages.Add(toolMsg) '将工具执行结果追加到消息数组
    Next
    ' ---- 构造下一次请求的请求体（带上所有工具的执行结果） ----
    hc = hc.Clone()
    jo("messages") = messages '此时消息数组包括所有工具执行结果
    hc.Content = jo.ToString()
Loop