Windows服务WebClient请求期间发生异常

Question

I receive the following error from a Windows Service application

   System.Net.WebException = {"An exception occurred during a WebClient request."}
    -2146233079
    InnerException = {"Configuration system failed to initialize"}

The same code on a Console application works fine.

The Service file has not setup Security on "Local Service" (in my test environment)

Could you point me out what could cause the error and how to solve it?

    Try
        Using client As New Net.WebClient
            Dim reqparm As New Specialized.NameValueCollection
            reqparm.Add("DeviceId", deviceId)
            reqparm.Add("StatusCode", statusCode)
            reqparm.Add("Type", "printer")
            reqparm.Add("Message", msg)
            Dim responsebytes = client.UploadValues("http://xxx.xxx.com/api/notification", "POST", reqparm)
            Dim responsebody = (New Text.UTF8Encoding).GetString(responsebytes)
        End Using
    Catch ex As Exception
        'do nothing
    End Try

my App.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <configSections>
    <section name="app" type="System.Configuration.NameValueSectionHandler" />
  </configSections>
  <app>
    <add key="version" value="0.0.1"/>
  </app>
</configuration>

Answer 1

The problem was in the App.config file. This the correct version, only one instance of <configSections> and should be the first element after <configuration> .

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="app" type="System.Configuration.NameValueSectionHandler" />
  </configSections>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <app>
    <add key="version" value="0.0.1"/>
  </app>
</configuration>