VB.NET如何检测客户端‘文件和打印机共享’启用状态

现有VPN检测逻辑优化 #

你当前写的VPN检测逻辑只匹配网卡名称，存在「网卡配置存在但实际未连通」的误判可能，补充网卡运行状态、类型判断即可，优化后代码如下：

Dim myInterfaceList As NetworkInterface() = NetworkInterface.GetAllNetworkInterfaces
' 同时校验网卡名称、运行状态、VPN网卡类型，避免误判
Dim myVPNRunning As Boolean = myInterfaceList.AsEnumerable().Any(
    Function(x) x.Name = "MyTestVPN"
    AndAlso x.OperationalStatus = OperationalStatus.Up
    AndAlso x.NetworkInterfaceType = NetworkInterfaceType.Ppp
)
chkProgress3.Checked = myVPNRunning

文件和打印机共享状态检测实现 #

不需要调用PowerShell，纯VB.NET原生实现即可，兼容性更好，不会触发系统脚本拦截。文件和打印机共享正常启用需要同时满足两个条件：

• 活动网卡（含VPN虚拟网卡）绑定了「Microsoft 网络的文件和打印机共享」服务组件
• Windows防火墙放行了文件和打印机共享的对应入站规则

前置准备 #

在项目中添加COM引用：右键项目 → 「添加引用」→ 切换到COM标签页 → 找到并勾选Windows Firewall Helper Class Library，确认添加即可，该组件是Windows系统自带，无需额外安装。

检测代码 #

首先引入所需命名空间：

Imports Microsoft.Win32
Imports System.Net.NetworkInformation
Imports NetFwTypeLib

核心检测函数：

''' <summary>
''' 检测活动网络下文件和打印机共享是否正常启用
''' </summary>
''' <returns>True=启用正常，False=未启用/配置异常</returns>
Private Function CheckFileAndPrinterSharingEnabled() As Boolean
    Dim serviceBinded As Boolean = False
    Dim firewallRuleAllowed As Boolean = False
    ' 文件和打印机共享服务组件固定GUID
    Const SHARING_SERVICE_GUID As String = "{4D36E978-E325-11CE-BFC1-08002BE10318}"
    ' 网卡设备类固定GUID
    Const NETWORK_ADAPTER_CLASS_GUID As String = "{4d36e972-e325-11ce-bfc1-08002be10318}"

    ' 1. 遍历所有已连接的网卡，检查是否绑定共享服务
    Dim activeAdapters = NetworkInterface.GetAllNetworkInterfaces() _
        .Where(Function(i) i.OperationalStatus = OperationalStatus.Up).ToList()
    Using adapterRootKey As RegistryKey = Registry.LocalMachine.OpenSubKey(
            $"SYSTEM\CurrentControlSet\Control\Class\{NETWORK_ADAPTER_CLASS_GUID}")
        If adapterRootKey IsNot Nothing Then
            For Each subKeyName In adapterRootKey.GetSubKeyNames()
                Using adapterKey As RegistryKey = adapterRootKey.OpenSubKey(subKeyName)
                    If adapterKey Is Nothing Then Continue For
                    Dim instanceId = TryCast(adapterKey.GetValue("NetCfgInstanceId"), String)
                    If String.IsNullOrEmpty(instanceId) Then Continue For
                    ' 匹配当前活动网卡
                    If activeAdapters.Any(Function(a) a.Id = instanceId) Then
                        Dim bindEntries = TryCast(
                            adapterKey.OpenSubKey("Ndi\Interfaces")?.GetValue("LowerRangeBindings"), 
                            String()
                        )
                        If bindEntries IsNot Nothing AndAlso bindEntries.Contains(SHARING_SERVICE_GUID) Then
                            serviceBinded = True
                            Exit For
                        End If
                    End If
                End Using
                If serviceBinded Then Exit For
            Next
        End If
    End Using

    ' 2. 检查防火墙是否放行共享规则
    Try
        Dim fwPolicy As INetFwPolicy2 = Activator.CreateInstance(
            Type.GetTypeFromProgID("HNetCfg.FwPolicy2")
        )
        Dim activeProfile = fwPolicy.CurrentProfileTypes
        For Each rule As INetFwRule In fwPolicy.Rules
            ' 通过系统内置规则组标识匹配，兼容多语言系统
            If rule.Grouping = "@FirewallAPI.dll,-28502" _
                AndAlso rule.Enabled _
                AndAlso (rule.Profiles And activeProfile) > 0 Then
                firewallRuleAllowed = True
                Exit For
            End If
        Next
    Catch
        ' 权限不足时返回失败，提示用户以管理员身份运行程序
        Return False
    End Try

    Return serviceBinded AndAlso firewallRuleAllowed
End Function

调用方式 #

在发起SQL Server连接请求前插入校验逻辑即可：

Dim sharingOk As Boolean = CheckFileAndPrinterSharingEnabled()
chkProgress4.Checked = sharingOk
If Not sharingOk Then
    MessageBox.Show("文件和打印机共享未正常启用，VPN环境下无法发现并连接SQL Server，请启用后重试", 
                    "前置校验不通过", 
                    MessageBoxButtons.OK, 
                    MessageBoxIcon.Warning)
    Return
End If

方案说明 #

• 适配Win7至Win11全版本Windows系统，非域环境完全可用，不依赖组策略配置
• 无PowerShell调用带来的版本兼容、执行权限拦截问题，运行稳定性更高
• 同时校验网卡绑定、防火墙规则两个维度，避免单维度检测的误判问题（很多场景下用户开了网卡绑定但防火墙拦截，依然无法正常访问SQL Server）
• 如果检测时提示权限不足，可以给程序添加应用程序清单文件，配置requestedExecutionLevel为requireAdministrator，要求程序启动时申请管理员权限即可。

内容的提问来源于stack exchange，提问作者Tim Hutchinson