我这么晚才来，也有同样的问题。对我来说，问题来了，因为我改变了pc名。

我使用的是SQL Server 2016和windows 10。

首先是允许远程连接到SQL Server。 我所做的就是键入sqlservermanager13。在开始菜单打开SQL Server配置管理器。确保TCP/IP状态为启用状态。

双击TCP/IP协议名称，检查TCP端口号。通常默认值是1433。

以下步骤通过使用Microsoft管理控制台(MMC)管理单元配置Windows防火墙的高级安全。高级安全Windows防火墙只配置当前配置文件。

To open a port in the Windows firewall for TCP access On the Start menu, click Run, type WF.msc, and then click OK. In the Windows Firewall with Advanced Security, in the left pane, right-click Inbound Rules, and then click New Rule in the action pane. In the Rule Type dialog box, select Port, and then click Next. In the Protocol and Ports dialog box, select TCP. Select Specific local ports, and then type the port number of the instance of the Database Engine, such as 1433 for the default instance. Click Next. In the Action dialog box, select Allow the connection, and then click Next. In the Profile dialog box, select any profiles that describe the computer connection environment when you want to connect to the Database Engine, and then click Next. In the Name dialog box, type a name and description for this rule, and then click Finish.

另一个需要配置的东西。

To open access to SQL Server when using dynamic ports On the Start menu, click Run, type WF.msc, and then click OK. In the Windows Firewall with Advanced Security, in the left pane, right-click Inbound Rules, and then click New Rule in the action pane. In the Rule Type dialog box, select Program, and then click Next. In the Program dialog box, select This program path. Click Browse, and navigate to the instance of SQL Server that you want to access through the firewall, and then click Open. By default, SQL Server is at C:\Program Files\Microsoft SQL Server\MSSQL13.MSSQLSERVER\MSSQL\Binn\Sqlservr.exe. Click Next. In the Action dialog box, select Allow the connection, and then click Next. In the Profile dialog box, select any profiles that describe the computer connection environment when you want to connect to the Database Engine, and then click Next. In the Name dialog box, type a name and description for this rule, and then click Finish.

看看微软的文档 配置Windows防火墙访问数据库引擎

我这么晚才来，也有同样的问题。对我来说，问题来了，因为我改变了pc名。

在做了上面提到的所有事情之后: http://blog.sqlauthority.com/2009/05/21/sql-server-fix-error-provider-named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server-microsoft-sql-server-error/ 对我来说还是没用。

以下步骤对我很有效:

开始>执行> cmd > sqlcmd -L

它将提示您服务器名。确保此服务器名称与SQL management studio的CONNECT to server框中试图连接的服务器名称相同。

我犯了这个愚蠢的错误，我一直使用MSSQLSERVER而不是使用这个服务器名。

希望这对像我一样犯愚蠢错误的人有所帮助。

谢谢。

您可以测试以下方法。

a Check the connection string of the project. b Go to services and restart SQLServer Instance. c Open 'SQLServer Configuration Manager' In the left panel select 'SQLServer Network Configuration' and expanding it Select 'Protocols for MSSQLServer' In the right panel dbl click on 'TCP/IP' In the 'Protocol' tab set the 'Enabled' to 'Yes' In the 'IP Addresses' tab scroll to down In the 'IPAll' set 'TCP Port' to 1433 d Open 'Firewall with advanced security' In the right tab select 'Inbound Rules'

在中间选项卡找到“本地端口”是1433的记录，如果你找不到它，尝试用以下级别创建它

In the Start menu, click Run, type 'WF.msc', and then click OK In the left panel click the 'Windows Firewall with Advanced Security' In the right panel right-click 'Inbound Rules', and then click 'New Rule' In the Rule Type dialog box, select 'Port', and then click Next In the Protocol and Ports dialog box, select 'TCP', and select 'Specific Local Ports', and then type the port number 1433, Click Next In the Action dialog box, select Allow the connection, and then click Next In the 'Profile' dialog box, checking the Domain, Private and Public, Then click Next In the 'Name' dialog box, type 'SQL 1433 Port' and for a description write description for own. Then click Finish

Then in the middle tab double click the found item(Instance) or created item of 'SQL 1433 Port' name by you. Select 'Scope' tab in opened dialog box(SQL Server Properties) In the Local PC Go to google.com in your Browser and search 'My IP'. then copy of your 'IP' Go to the remote server and in the 'SQL Server Properties' dialog box of 'Scope' tab, in the 'Remote IP Address' select the 'These IP Addresses' option and click 'Add' button In the opened dialog box(IP Address) select 'This IP Address or Subnet' option and paste your 'IP', click OK button.

为什么这个错误是如此烦人和嘈杂，只是因为它可以发生在不同的情况。

我已经做了上面所有的方法，但还是很糟糕。所以，在向下浏览之前，确保你和我做了同样的事情。

也许我不能立即解决你的问题，但我可以给你指明一个方向或思路(最后滑下来的那个人)。我已经开始思考我的运行程序的错误发生后，我确保实例名是明确正确的，并设置我的数据库，以允许远程控制以下的方法。之后，我怀疑我的SQL连接代码片段发生了错误。

我的问题解决方案:

检查我的sqlconnection函数

单击以查看其配置

新建连接

选择你的服务器名

对我来说，思考在联系的过程中到底发生了什么是有效的。希望我的想法能引导你改正错误。