SQLConnection错误“用户登录失败” C＃

Question

I created a database (without user or password) as a service-based database.

Now I'm trying to insert to a database, but there is a error "Login failed for user"

I have this code:

string J_connetionString1 = null;
SqlConnection J_connection1;
SqlDataAdapter J_adapter1 = new SqlDataAdapter();
string J_sql1 = null;
J_connetionString1 = @"Data Source=.\SQLEXPRESS;Initial Catalog=J_InsData";

J_connection1 = new SqlConnection(J_connetionString1);
J_sql1 = "update instinfo set instinfoNAME = textBox2.text where instinfoID ='1'";
try
{
    J_connection1.Open();
    J_adapter1.UpdateCommand = J_connection1.CreateCommand();
    J_adapter1.UpdateCommand.CommandText = J_sql1;
    J_adapter1.UpdateCommand.ExecuteNonQuery();
    MessageBox.Show("Row updated !! ");
}
catch (Exception ex)
{
    MessageBox.Show(ex.ToString());
}

i can't comment so i edited the Q.

this error appeared by using this code

error : system.Data.sqlclint.sqlexpection(0x80131904) cannot open database "J_InsData" request by the login. the login faild login failed for user J-PC\\J

code: J_connetionString1 = @"Data Source=.\\SQLEXPRESS;Initial Catalog=J_InsData;Trusted_Connection=True;Integrated Security=SSPI";

Answer 1

You need to tell SQL Server which user credentials to use for a connection.

Hence you should provide a user id and password of SQL Server user in your connection string.

Server=myServerAddress;Database=myDataBase;User Id=myUsername;
Password=myPassword;

On the other hand if the SQL erver is configured to accept windows domain users, you can use Integrated Security=SSPI or Trusted_Connection=True in the connection string.

Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;
Server=myServerAddress;Database=myDataBase;Integrated Security=SSPI;

Answer 2

Have you tried adding the following to your connection string?

Integrated Security=True

or

Integrated Security=SSPI

which is pretty mcuh the same as True.

This LINK might be useful for you as well.