预览群发消息

群发的次数有限，所以最好先通过预览调整好消息内容再群发。

预览的次数是每天100次，所以也不要滥用。

预览各种类型的群发消息，代码基本是相同的。

预览文本消息

参考代码：

Dim url As String = "https://api.weixin.qq.com/cgi-bin/message/mass/preview?access_token={0}"
Dim hc As New HttpClient(CExp(url, Functions.Execute("GetAccessToken")))
Dim jo As New JObject()
jo("touser") = "ofjtFwBSZ5cNqTKLSKx2TNEAxfBI" '接收预览信息的OpenID
jo("text") = New JObject
jo("text")("content") = "需要群发的文本消息"
jo("msgtype") = "text"
hc.Content = jo.ToString()
jo = JObject.Parse(hc.GetData)
If jo("errcode") = "0" Then
    MessageBox.Show("已经发送预览消息,请注意查看")
Else
    MessageBox.Show(jo.ToString)
End If

预览图片消息

必须事先将要群发的图片上传到微信服务器，因为群发的只是图片素材的ID，参考代码:

Dim url As String = "https://api.weixin.qq.com/cgi-bin/message/mass/preview?access_token={0}"
Dim hc As New HttpClient(CExp(url, Functions.Execute("GetAccessToken")))
Dim jo As New JObject()
jo("touser") = "ofjtFwBSZ5cNqTKLSKx2TNEAxfBI" '接收预览信息的OpenID
jo("image") = New JObject
jo("image")("media_id") = "XuVl2KV07GQG2J0Gv6QLLzErZRJ3ug1l1PQtg4KUgJw" '已经上传的永久图片素材ID
jo("msgtype") = "image"
hc.Content = jo.ToString()
jo = JObject.Parse(hc.GetData)
If jo("errcode") = "0" Then
    MessageBox.Show("已经发送预览消息,请注意查看")
Else
    MessageBox.Show(jo.ToString)
End If

预览图文消息

必须事先将要群发的图文消息上传到微信服务器，因为群发的只是图文消息的ID，参考代码:

Dim url As String = "https://api.weixin.qq.com/cgi-bin/message/mass/preview?access_token={0}"
Dim hc As New HttpClient(CExp(url, Functions.Execute("GetAccessToken")))
Dim jo As New JObject()
jo("touser") = "ofjtFwBSZ5cNqTKLSKx2TNEAxfBI" '接收预览信息的OpenID
jo("mpnews") = New JObject
jo("mpnews")("media_id") = "XuVl2KV07GQG2J0Gv6QLLzTT6WJPsP0yUDdwnoueJio" '已经上传的永久图文素材ID
jo("msgtype") = "mpnews"
hc.Content = jo.ToString()
jo = JObject.Parse(hc.GetData)
If jo("errcode") = "0" Then
    MessageBox.Show("已经发送预览消息,请注意查看")
Else
    MessageBox.Show(jo.ToString)
End If

预览语音消息

必须事先将要群发的语音文件上传到微信服务器，因为群发的只是语音素材的ID，参考代码:

Dim url As String = "https://api.weixin.qq.com/cgi-bin/message/mass/preview?access_token={0}"
Dim hc As New HttpClient(CExp(url, Functions.Execute("GetAccessToken")))
Dim jo As New JObject()
jo("touser") = "ofjtFwBSZ5cNqTKLSKx2TNEAxfBI" '接收预览信息的OpenID
jo("voice") = New JObject
jo("voice")("media_id") = "XuVl2KV07GQG2J0Gv6QLL5Ciga6xkphUAbcNEk2UUrE" '已经上传的永久语音素材ID
jo("msgtype") = "voice"
hc.Content = jo.ToString()
jo = JObject.Parse(hc.GetData)
If jo("errcode") = "0" Then
    MessageBox.Show("已经发送预览消息,请注意查看")
Else
    MessageBox.Show(jo.ToString)
End If

预览视频消息

必须事先将要群发的视频文件上传到微信服务器，因为群发的只是视频素材的ID，参考代码:

Dim url As String = "https://api.weixin.qq.com/cgi-bin/message/mass/preview?access_token={0}"
Dim hc As New HttpClient(CExp(url, Functions.Execute("GetAccessToken")))
Dim jo As New JObject()
jo("touser") = "ofjtFwBSZ5cNqTKLSKx2TNEAxfBI" '接收预览信息的OpenID
jo("mpvideo") = New JObject
jo("mpvideo")("media_id") = "XuVl2KV07GQG2J0Gv6QLL0Bi3oDe1o9RvMENqM-oZ8A" '已经上传的永久视频素材ID
jo("msgtype") = "mpvideo"
hc.Content = jo.ToString()
jo = JObject.Parse(hc.GetData)
If jo("errcode") = "0" Then
    MessageBox.Show("已经发送预览消息,请注意查看")
Else
    MessageBox.Show(jo.ToString)
End If