Question

SqlConnection con = new SqlConnection(@"Server=.\SQLEXPRESS;AttachDbFilename='C:\HashTags.mdf';Integrated Security=True;User Instance=True");

con.Open();
String queryStr = "SELECT name FROM ttable WHERE name LIKE '*%'";
SqlCommand com = new SqlCommand(queryStr, con);
SqlDataReader sdr = com.ExecuteReader();

while (sdr.Read())
{
    this.trendingBx.Text = sdr.GetValue(0).ToString();
}

sdr.Close();

Could anyone tell me why I get this error:

A database with the same name exists, or specified file cannot be
opened, or it is located on UNC share.

Answer 1

Are you sure the database is not already attached? If it is you should use:

Data Source=.\SQLEXPRESS;Database=your database name;Integrated Security=SSPI