连接数据库时出现
Connection Timeout Expired. The timeout period elapsed while
attempting to consume the pre-login handshake acknowledgement. This
could be because the pre-login handshake failed or the server was
unable to respond back in time. The duration spent while attempting to
connect to this server was - [Pre-Login] initialization=0;
handshake=14997;

提示

Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=0; handshake=14997;

提示
Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=0; handshake=14997;

An unhandled exception occurred while processing the request.
SqlSugarException: English Message : Connection open error . Connection Timeout Expired. The timeout period elapsed during the post-login phase. The connection could have timed out while waiting for server to complete the login process and respond; Or it could have timed out while attempting to create multiple active connections. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=48; handshake=124; [Login] initialization=0; authentication=0; [Post-Login] complete=14000;

An unhandled exception occurred while processing the request.
SqlSugarException: English Message : Connection open error . A connection was successfully established with the server, but then an error occurred during the login process. (provider: TCP Provider, error: 35 - An internal exception was caught)

原因：

.net core 的System.Data.SqlClient支持的最低SqlServer版本是2008 r2 SP3,小于这个版本的就会报这个错。

解决

方式1：.netcore 连接使用 sqlserver
.net core 的System.Data.SqlClient支持的最低SqlServer版本是2008 r2 SP3 请先检查数据库版本

方式2：通过sqlserver控制管理工具，重启sqlserver服务进程

其他信息

Microsoft SQL Server 2008 R2 (SP1)
10.50.2550.0 (X64) Jun 11 2012 16:41:53 Copyright (c) Microsoft Corporation Standard Edition (64-bit) on Windows NT 6.1 (Build 7601: Service Pack 1)

Connection string:

Data Source=192.168.1.6;Initial Catalog=DBName;Persist Security Info=False;User ID=username;Password=pass

This issue may be related to #16528.

Unfortunately, we cannot upgrade our SQL server service pack. The same application works fine on Windows. This also impacts Entity Framework .

Code:

using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(queryString, connection);
    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    try
    {
        while (reader.Read())
        {
            Console.WriteLine(String.Format("{0}, {1}",
            reader["Id"], reader["Email"]));
        }
    }
    catch(Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }
}