The TCP/IP connection to the host localhost, port 1433 has failed. Error: Connection refused: connect. Please verify the connection properties and check that a SQL Server instance is running on the host and accepting TCP/IP connections at the port, and that no firewall is blocking TCP connections to the port.
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连接代码应该是有问题，特别是你的连接串
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去数据库看看你的SQLServer 端口号是不是默认端口1433 打开TCP/IP协议
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sqlserver有个tcp/ip服务没开
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检查下你的端口号吧，看是不是1433.TCP/IP要开启，然后重启电脑再试一次吧