无法连接到本地 SQL Server 数据库

Question

Just trying to do a simple local database connect to Microsoft SQL Server in Visual Studio. Trying to figure out why it's not connecting. I made a user specifically for this and have the correct username and password. I omitted the User Id and Password from this purposely. Seems to be throwing an error at my connection string, what am I doing wrong?

System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

My code:

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Assetmvc
{
    public partial class SearchPage : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            // Connect to the db
            string connStr = "Server=localhost;Database=AssetTracking;User Id=;Password=; ";
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();

            // Create a command
            SqlCommand cmd = new SqlCommand("SELECT [EmployeeId],[FirstName],[LastName],[HiredDate],[FiredDate],[CurrentItems],[SupervisorId],[SupervisorName] From [dbo].Employees");
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.Connection = conn;

            string temp = "";

            // Read from database
            SqlDataReader reader = cmd.ExecuteReader();

            while(reader.Read())
            {
                temp += reader["EmployeeId"].ToString();
                temp += reader["FirstName"].ToString();
                temp += reader["LastName"].ToString();
                temp += reader["HiredDate"].ToString();
                temp += reader["FiredDate"].ToString();
                temp += reader["CurrentItems"].ToString();
                temp += reader["SupervisorId"].ToString();
                temp += reader["SupervisorName"].ToString();
                temp += 

                temp += "<br/>";
            }

            conn.Close();

            lbl_test.Text = temp; 
        }
    }
}

Answer 1

If you're using SQL Server Express and used all the defaults when installing, then you have a SQL Server named instance with a name of SQLEXPRESS - and therefore, you need to use this connection string:

string connStr = "Server=localhost\\SQLEXPRESS;Database=AssetTracking;User Id=;Password=; ";

Note that you need to use localhost\\SQLEXPRESS to connect to the named instance with an instance name of SQLEXRPESS .

Answer 2

After troubleshooting all day this guide has helped a lot.

https://success.scribesoft.com/s/article/Named-Pipes-Provider-Error-40

Although after doing that I ended up just using the connection string provided in the properties box after clicking my server in Sql server explorer.

I want to thank everyone who didn't downvote and actually helped out I really appreciate it. I'm marking Marc_S as the answer but wanted to add this for any one else who might read this.