在c#中以多种形式使用sql server 2005的应用程序角色表达

Question

我有一个 C# .net winforms 应用程序，它有两个使用连接字符串连接到 sql express 的表单。

form1 使用受信任的连接连接到 sql。连接字符串在 app.config 文件中给出。

现在，单击 form1 上的一个按钮会更改与应用程序角色凭据的连接。

现在，form2 打开，它有一个按钮，点击该按钮需要使用应用程序角色设置创建数据库。

那么我如何使用在form1中创建的应用程序角色设置到form2中。因为要执行数据库创建查询，Form2 需要一个新的连接对象。

那么，我必须添加另一个 app.config 文件还是其他什么？

------------已编辑---------- ------------------------------

public partial class Form1 : Form
{
    SqlConnection conn = new SqlConnection();

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
             //new code for using conenction string from app.config file added 
                //  Read appSettings
                    string title = ConfigurationSettings.AppSettings["ApplicationTitle"];
                    string connectString =
                    ConfigurationSettings.AppSettings["ConnectionString"];
                    conn.ConnectionString = connectString;
           //new code ends

        conn.Open();
        string setapprole = "sp_setapprole 'my_app' , 'app_pass' ";
        SqlCommand cmd_app = new SqlCommand(setapprole, conn);
        SqlDataReader approle_reader = cmd_app.ExecuteReader();
        approle_reader.Close();

        Form2 f2 = new Form2();
        f2.Show();
    }

}

--------------------------------FORM2.CS------------ ------------------

public partial class Form2 : Form
{
   //how to connect to the database, 
    public Form2()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {  
        string query = "create database new_db";
         //I WANT TO USE the conn object here, 
          //& want the connection to use the application role
         // which was set in Form1.cs 
        SqlCommand cmd = new SqlCommand(query, conn); 
        SqlDataReader createdb = cmd.ExecuteReader();

    }
}

---------------EDITED-1----------------------------- -----

我的 app.config 文件：

`xml 版本="1.0" 编码="utf-8"

配置

应用设置 add key="ApplicationTitle" value="设置数据库、表和权限" 添加键=“连接字符串” value="服务器=本地主机；Trusted_Connection=true" 应用设置

配置

Answer 1

使用SqlConnectionStringBuilder 修改连接参数，然后打开与数据库的新连接。

编辑

public partial class Form1 : Form
    {
        SqlConnection conn = new SqlConnection("Data Source=TODO;Initial Catalog=TODO;Integrated Security=True");

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (SqlCommand command = new SqlCommand("sp_setapprole 'my_app' , 'app_pass' ", conn))
            {
                command.CommandType = CommandType.Text;
                conn.Open();
                command.ExecuteNonQuery();
            }
            // The application role is set and remains active until the user disconnects

            Form2 f2 = new Form2(conn);
            f2.Show();
        }
    }

    public partial class Form2 : Form
    {
        SqlConnection conn = null;
        //how to connect to the database, 
        public Form2(SqlConnection conn)
        {
            InitializeComponent();
            this.conn = conn;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                using (SqlCommand command = new SqlCommand("create database new_db", conn))
                {
                    command.CommandType = CommandType.Text;
                    command.ExecuteNonQuery();
                }
            }
            finally
            {
                // Important to close the DB connection (at which point the approle becomes inactive)
                conn.Close();
            }

        }
    }