在C#项目中如何应对SQL注入问题

在C#项目中，应对SQL注入问题的最佳方法是使用参数化查询（Parameterized Query）或预编译语句（Prepared Statement）

1. 使用SqlCommand和参数化查询：

using System.Data.SqlClient;

string connectionString = "your_connection_string";
string sqlQuery = "SELECT * FROM Users WHERE Username = @username AND Password = @password";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    using (SqlCommand command = new SqlCommand(sqlQuery, connection))
    {
        // 添加参数并设置值
        command.Parameters.AddWithValue("@username", userInputUsername);
        command.Parameters.AddWithValue("@password", userInputPassword);

        connection.Open();

        using (SqlDataReader reader = command.ExecuteReader())
        {
            // 处理查询结果
        }
    }
}

2. 使用SqlParameter：

using System.Data.SqlClient;

string connectionString = "your_connection_string";
string sqlQuery = "SELECT * FROM Users WHERE Username = @username AND Password = @password";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    using (SqlCommand command = new SqlCommand(sqlQuery, connection))
    {
        // 创建参数并设置值
        SqlParameter usernameParam = new SqlParameter("@username", SqlDbType.VarChar);
        usernameParam.Value = userInputUsername;

        SqlParameter passwordParam = new SqlParameter("@password", SqlDbType.VarChar);
        passwordParam.Value = userInputPassword;

        // 将参数添加到命令中
        command.Parameters.Add(usernameParam);
        command.Parameters.Add(passwordParam);

        connection.Open();

        using (SqlDataReader reader = command.ExecuteReader())
        {
            // 处理查询结果
        }
    }
}

3. 使用Dapper库：

安装Dapper NuGet包：

Install-Package Dapper

示例代码：

using System.Data.SqlClient;
using Dapper;

string connectionString = "your_connection_string";
string sqlQuery = "SELECT * FROM Users WHERE Username = @username AND Password = @password";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();

    var queryResult = connection.Query(sqlQuery, new { username = userInputUsername, password = userInputPassword });

    // 处理查询结果
}

通过使用参数化查询或预编译语句，您可以有效地防止SQL注入攻击，因为参数值会被自动转义，而不是直接插入到SQL语句中。