To create a connection to a database

using (SqlConnection connection = new SqlConnection("Data Source=(local);Initial Catalog=AdventureWorks2014;Integrated Security=SSPI"))
{
    connection.Open();
}

To get data from the database is by using a SqlDataAdapter.

DataTable table = new DataTable();
using (SqlConnection connection = new SqlConnection("Data Source=(local);Initial Catalog=AdventureWorks2014;Integrated Security=SSPI"))
using (SqlCommand cmd = new SqlCommand("SELECT BusinessEntityID AS ID, FirstName, MiddleName, LastName FROM Person.Person", connection))
using (SqlDataAdapter adapter = new SqlDataAdapter(cmd))
{
    adapter.Fill(table);
}
// Use table here...

To select a subset of persons by first name.

string firstName = "John";
using (SqlConnection connection = new SqlConnection("Data Source=(local);Initial Catalog=AdventureWorks2014;Integrated Security=SSPI"))
using (SqlCommand cmd = new SqlCommand("SELECT BusinessEntityID AS ID, FirstName, MiddleName, LastName FROM Person.Person WHERE FirstName = '" + firstName + "'", connection))
{
    // ...
}

2楼: Originally posted by FMStation at 2016-09-13 20:17:12
http://www.codeproject.com/Articles/837599/Using-Csharp-to-connect-to-and-query-from-a-SQL-da

To create a connection to a database

using (SqlConnection connection = new SqlConnection(" ...