How to get multiple column values from DB in session variabl

below is my code

 

protected void ValidateUser(object sender, EventArgs e)
{
int userId = 0;
string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand("Validate_User"))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@Username", txtUname.Text.Trim());
cmd.Parameters.AddWithValue("@Password", txtPassword.Text.Trim());
cmd.Connection = con;
con.Open();
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
sda.Fill(dt);
userId = Convert.ToInt32(cmd.ExecuteScalar());
con.Close();
if (dt.Rows.Count > 0)
{
Session["uid"] = dt.Columns[0].ToString();
Session["Username"] = dt.Columns[1].ToString();
Session["city"] = dt.Columns[2].ToString();
Response.Redirect("Redirectform.aspx");
Session.RemoveAll();
}
else
{
lblmsg.Text = "You're username and word is incorrect";
lblmsg.ForeColor = System.Drawing.Color.Red;

}
}
switch (userId)
{
case -1:
lblmsg.Text = "Username and/or password is incorrect.";
break;
case -2:
lblmsg.Text = "Account has not been activated.";
break;
default:
//FormsAuthentication.RedirectFromLoginPage(Login1.UserName, Login1.RememberMeSet);
break;
}
}
}


This is my stored Procedure..validated user

ALTER PROCEDURE [dbo].[Validate_User]
@Username NVARCHAR(20),
@Password NVARCHAR(20)
AS
BEGIN
SET NOCOUNT ON;
DECLARE @UserId INT, @LastLoginDate DATETIME

SELECT @UserId = UserId, @LastLoginDate = LastLoginDate
FROM Users WHERE Username = @Username AND [Password] = @Password

IF @UserId IS NOT NULL
BEGIN
IF NOT EXISTS(SELECT UserId FROM UserActivation WHERE UserId = @UserId)
BEGIN
UPDATE Users
SET LastLoginDate = GETDATE()
WHERE UserId = @UserId
SELECT @UserId [UserId] -- User Valid
END
ELSE
BEGIN
SELECT -2 -- User not activated.
END
END
ELSE
BEGIN
SELECT -1 -- User invalid.
END
END