select*仅返回一个值

Question

我想从表Account中选择多个(所有)值.

string query = "SELECT * FROM Account";
        SqlConnection connection = new SqlConnection(connectionString);
        SqlCommand command = new SqlCommand(query, connection);
        SqlDataReader reader;
        connection.Open();
        reader = command.ExecuteReader();
        reader.Read();
        label1.Text = reader["PasswordHash"].ToString();
        connection.Close();

为什么这总是只返回第一行.实际上它返回一行,因为如果我在where子句中设置类似的where id = 2 and id = 3东西仍然只返回一个值.从Management Studio检查表有多个值,查询运行应该如此.

提前致谢.

Answer 1

因为您没有遍历查询结果,所以它只显示一个结果.

string query = "SELECT * FROM Account";
    SqlConnection connection = new SqlConnection(connectionString);
    SqlCommand command = new SqlCommand(query, connection);
    SqlDataReader reader;
    connection.Open();
    reader = command.ExecuteReader();
    While(reader.Read())
{
    label1.Text += " " +reader["PasswordHash"].ToString();
}
    connection.Close();

上面的代码循环遍历查询结果,并在分配给的连接字符串中为您提供所需的内容label1.text.您还可以通过将查看结果Console.WriteLine(reader["PasswordHash"].ToString());的while循环