如何在更改之前检查旧密码是否匹配？

Question

我有这个代码：

//Update login query
string sql = "ALTER LOGIN " + login.ToUpper() + " WITH PASSWORD = '" + password + "' OLD_PASSWORD = '" + oldpassword + "'";

//Try connection and execute
using (SqlConnection connection = new SqlConnection(GetConnection()))
{
     connection.Open();

     SqlCommand command = new SqlCommand(sql, connection);
     command.CommandType = System.Data.CommandType.Text;
     var result = command.ExecuteScalar();
     connection.Close();
}

此 sql 查询更改数据库中的登录密码。请注意，它需要旧密码才能继续。不过，如果我传递了一个错误的旧密码，那么它会抛出一个 SQLException:

Cannot alter the login 'SEVA', because it does not exist or you do not have permission.

如何在执行此查询之前检查旧密码是否正确，以便向用户显示错误消息？

Answer 1

试试这个。你需要在 catch 中添加一些东西来告诉用户他没有输入正确的密码

        //Update login query
        string sql = "ALTER LOGIN " + login.ToUpper() + " WITH PASSWORD = '" + password + "' OLD_PASSWORD = '" + oldpassword + "'";

        try {
        //Try connection and execute
        using (SqlConnection connection = new SqlConnection(GetConnection()))
        {
             connection.Open();

             SqlCommand command = new SqlCommand(sql, connection);
             command.CommandType = System.Data.CommandType.Text;
             var result = command.ExecuteScalar();
             connection.Close();
        }
    }
    catch(SQLException)
    {
//Do something here to tell the user something went wrong
    }

如何在更改之前检查旧密码是否匹配？

How to check if old password matches before change it?

c#

sql

.net

ado.net