无法插入到SQL Server数据库

Question

using (Connection = new SqlConnection(connectionstring))                
{
    SqlCommand voegtoe = new SqlCommand("INSERT INTO Speler(Naam, Rugnummer, Leeftijd) VALUES(@Naam, @Rugnummer, @Leeftijd)");

    voegtoe.CommandType = CommandType.Text;
    voegtoe.Connection = Connection;
    voegtoe.Parameters.AddWithValue("@Naam", textBox1.Text);
    voegtoe.Parameters.AddWithValue("@Rugnummer", textBox2.Text);
    voegtoe.Parameters.AddWithValue("@Leeftijd", textBox3.Text);

    Connection.Open();
    voegtoe.ExecuteNonQuery();            
}

If I open my Database there's nothing added to it. I think it should add the text what the user puts in the textboxes.

The connection string is:

Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirector‌​y|\Speler.mdf;Integr‌​ated Security=True

Answer 1

There's nothing wrong with the code. I suspect that your connection string uses a User instance database, ie it has the AttachDBFilename and User Instance=true keywords:

Data Source=.\SQLEXPRESS; AttachDBFilename=|DataDirectory|\db.mdf; User Instance=true;...

That means that each user that tries to attach to the database file gets his own copy. When you try to check the data with SSMS you see a different copy of the database.

Apart from causing confusion, this feature is deprecated and will be removed in the future.

Just create a proper database in your database server and connect to it by specifying its name:

Data Source=.\SQLEXPRESS; Initial Catalog=MyDB;...

You can create the database either from the New Database menu in SSMS, or with a CREATE DATABASE MyDB command

You can find more information in Bad habits : Using AttachDBFileName by Aaron Bertrand

Answer 2

What happens when your query hasn't been able to run? If you would get an Exception you have to retry your insert.

The ExecuteNonQuery() method is able to return the amount of rows inserted.