C＃-“用户'用户名'登录失败（SQL Server 2014）

Question

I'm trying to connect to SQL Server 2014 using my C# code

<connectionStrings>
    <add name="ConnectionString" 
         connectionString="Data Source=IP\\SQLNameSERVER,1433;Network Library=DBMSSOCN; Initial Catalog=MyDB; User ID=Username; Password=password;"/>
</connectionStrings>

string ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

using (SqlConnection cn = new SqlConnection(ConnectionString))
{
     query = "SELECT * FROM [MyTable]";

     using (SqlCommand commandUserPortal = new SqlCommand(query, cn))
     {
         cn.Open();
     }
  }

but I get an error message:

Login failed for user 'Username'.

When I use the same credentials to connect to DB through SQL Server Management Studio, it works fine without any issues.

The user has db_datareader permission.

I also tried

<connectionStrings>
    <add name="ConnectionString" 
         connectionString="Data Source=IP\\SQLNameSERVER,1433;Network Library=DBMSSOCN; Initial Catalog=MyDB; User ID=Username; Password=password;
         providerName="System.Data.SqlClient"/>
</connectionStrings>

Answer 1

Use an accurate connection string via using Add connection from Visual studio.

How:-

Follow the next screen shots:-

1) View >> Server Explorer

2) Add Connection

3) Choose data source >> SQL Server

4) Type Server Name , SQL Server authentication , type username and password , and choose database .

5) Click Test Connection button.

6) The Connection that you created will be added here

7) Right click and choose properties

8) Finally copy and paste the connection string and use it , and replace the stars (********) with your password

Answer 2

Try to change setting in sql server for you database. Allow both sql and windows authentication. For steps with images, check here . I hope that you are not using windows authentication and also the DB server is reachable by your network. Everything else is looking ok to me.

Answer 3

try to change your Connection String:

<add name="ConnectionString" connectionString="Data source=IP\SQLNameSERVER;Initial Catalog=DBname;User=Username;Password=Password; connection timeout=6000;" />

Also try to change your Code:

from:

using (SqlConnection cn = new SqlConnection(ConnectionString))
{
     query = "SELECT * FROM [MyTable]";

     using (SqlCommand commandUserPortal = new SqlCommand(query, cn))
     {
         cn.Open();
     }
  }

to:

using (SqlConnection cn = new SqlConnection(ConnectionString))
{
     query = "SELECT * FROM [MyTable]";
     cn.Open();
     using (SqlCommand commandUserPortal = new SqlCommand(query, cn))
     {

     }
  }

Answer 4

Use the following as Connection String

<add name="DefaultConnection" connectionString="data source=192.168.0.1; initial catalog=DBNAME;persist security info=True;user id=UserId;password=Password;MultipleActiveResultSets=True ; Connect Timeout=10000" providerName="System.Data.SqlClient" />

Replace your Database name in the catalog,user id in user id and passeord in password