Question

C# 中为何 显示 ExecuteReader 要求已打开且可用的连接。连接的当前状态为已关闭。

SqlConnection conn = null;
SqlCommand comm = null;
string strConnection;
// bool flag = false;
string userId = TextBox1.Text;
string password = TextBox2.Text;
try
{
strConnection = "server=(local);database=HRManager;integrated security=SSPI";
conn.Open();
conn = new SqlConnection();
conn.ConnectionString = strConnection;
// conn.Open();
}
catch
{
Label2.Text = "连接数据库失败！";
}
string sql = "select * from [user] where userId='" + TextBox1.Text.Trim() + "' and password='" + TextBox2.Text.Trim() + "'";
comm = new SqlCommand(sql, conn);
// comm.CommandText = sql;

SqlDataReader reader = comm.ExecuteReader();
if (reader.HasRows == true)
{
Response.Redirect("main.aspx");

}
else
{
// Label3 = "用户不存在！";
}

Answer 1

try
{
strConnection = "server=(local);database=HRManager;integrated security=SSPI";
conn.Open();
conn = new SqlConnection();
conn.ConnectionString = strConnection;
// conn.Open();
}
你把第老兄一个conn.open()去掉，因为这袭薯个时候你拍含者还没有初始化conn呢~~

追问

我原本是用的下面那个 conn.Open();
，可是有人说要放上面 ，可是不管放哪边都是一样 都显示的同样的问题

Answer 2

conn.Open();
conn = new SqlConnection();
conn.ConnectionString = strConnection;
顺序有缓返问乱模题
conn.Open();放下边试试哗哪缓

追问

放下面了的 ，可是他还是这句有问题 “SqlDataReader reader = comm.ExecuteReader();”
ExecuteReader 要求已打开且可用的连接。连接的当前状态为已关闭。