generate LINQ module from this C# module for data set

Question

I am trying to change the below code as LINQ. But I am unable to do this, please guide me. 

 

private void getData(AutoCompleteStringCollection dataCollection)

{

string connetionString = null;

SqlConnection connection ;

SqlCommand command ;

SqlDataAdapter adapter = new SqlDataAdapter();

DataSet ds = new DataSet();

connetionString = "Data Source=.;Initial Catalog=pubs;User ID=sa;password=zen412";

string sql = "SELECT DISTINCT [fname] FROM [employee]";

connection = new SqlConnection(connetionString);

try

{

connection.Open();

command = new SqlCommand(sql, connection);

adapter.SelectCommand = command;

adapter.Fill(ds);

adapter.Dispose();

command.Dispose();

connection.Close();

foreach (DataRow row in ds.Tables[0].Rows)

{

dataCollection.Add(row[0].ToString());

}

}

catch (Exception ex)

{

MessageBox.Show("Can not open connection ! ");

}

}

I want to get the user_name from my AppUser table. How can I do this?