Error: login failed for user SQL Server

Question

I'm trying to connect to SQL Server using my C# code, but unable to establish the connection it keeps throwing the exception login failed for user abcdef.

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

<connectionStrings>
    <add name="Conn" 
         connectionString="Server=xxxx\yyyy;User ID=abcdef;Password=******;Initial Catalog=mytestDB;"/>
</connectionStrings>

string strDBCon = ConfigurationManager.ConnectionStrings["Conn"].ToString();
SqlConnection sqlConnection = new SqlConnection();
sqlConnection.ConnectionString = strDBCon;
sqlConnection.Open();

Answer 1

I'm not sure whether .ToString() gives back the correct representation of the connection string. Anyway, that would be the correct one:

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

Answer 2

<connectionStrings>
<add name="NameOFConnectionString" connectionString="Data Source=Server;Initial Catalog=DatabaseName;User ID=User;Password=Pwd"
providerName="System.Data.SqlClient" />

then call the connection string

SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["NameOFConnectionString"].ToString();

Answer 3

也许您使用可信连接，并且应该在连接字符串中添加“ Trusted_Connection = True”。