How do I connect to an MDF database file?

Question

I'm experimenting in connecting a C# app to an MDF database for the first time, and I need a little help..

I made a small MDF database file in Visual Studio 2010, then created another project and imported the file into the project itself.

I am not trying to connect to the MDF file via code. Here the code I'm using:

namespace DBtestApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        System.Data.SqlClient.SqlConnection con;
        private void Form1_Load(object sender, EventArgs e)
        {
            con = new System.Data.SqlClient.SqlConnection();
            con.ConnectionString = "DataSource=.\\SQLEXPRESS; AttachDbFilename =SampleDatabase.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";
            con.Open();
            MessageBox.Show("Connection opened");
            con.Close();
            MessageBox.Show("Connection closed");
        }
    }
}

When I run the application, I get an exception at the line where I define the connection string, and the exception has this message at the top of the stack:

System.ArgumentException: Keyword not supported: 'datasource'.

Can someone point me in the right direction?

Answer 1

Add space between Data Source

 con.ConnectionString = @"Data Source=.\SQLEXPRESS;
                          AttachDbFilename=c:\folder\SampleDatabase.mdf;
                          Integrated Security=True;
                          Connect Timeout=30;
                          User Instance=True";

Answer 2

string sqlCon = @"Data Source=.\SQLEXPRESS;" +
                @"AttachDbFilename=|DataDirectory|\SampleDB.mdf;
                Integrated Security=True;
                Connect Timeout=30;
                User Instance=True";
SqlConnection Con = new SqlConnection(sqlCon);

The filepath should have |DataDirectory| which actually links to "current project directory\\App_Data\\" or "current project directory" and get the .mdf file.....Place the .mdf in either of these places and should work in visual studio 2010.And when you use the standalone application on production system, then the current path where the executable file is, should have the .mdf file.

Answer 3

转到服务器资源管理器>您的数据库>右键单击>属性> ConnectionString并复制连接字符串并复制到connectiongstring代码:)

Answer 4

对于Visual Studio 2015，连接字符串为：

"Data Source=(localdb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|Database1.mdf;Integrated Security=True"

Answer 5

Server=.\SQLExpress;AttachDbFilename=c:\mydbfile.mdf;Database=dbname; Trusted_Connection=Yes;

Answer 6

SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=E:\Samples\MyApp\C#\bin\Debug\Login.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True");

this is working for me... Is there any way to short the path? like

SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=\bin\Debug\Login.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True");

Answer 7

Alternative solution, where you can have the database in the folder you want inside the solution. That worked for me:

.ConnectionString(@"Data Source=LocalDB)\MSSQLLocalDB;
                    AttachDbFilename="+AppDomain.CurrentDomain.BaseDirectory+"Folder1\\Folder2\\SampleDatabase.mdf" + ";
                    Integrated Security=True;")

Answer 8

Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename="C:\Users\hasif\Documents\Visual Studio 2015\Projects\vgsoft\SqlserverRepo\data\Database1.mdf";Integrated Security=True;Connect Timeout=30

1

2

ConnectionString