当C#使用output参数调用存储过程时，不查询任何数据

using System;
using System.Data;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "YourConnectionString";
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();

            SqlCommand command = new SqlCommand("YourStoredProcedure", connection);
            command.CommandType = CommandType.StoredProcedure;

            // 添加输入参数
            command.Parameters.AddWithValue("@InputParameter", "YourValue");

            // 添加输出参数
            SqlParameter outputParameter = new SqlParameter();
            outputParameter.ParameterName = "@OutputParameter";
            outputParameter.SqlDbType = SqlDbType.VarChar;
            outputParameter.Size = 50;
            outputParameter.Direction = ParameterDirection.Output;
            command.Parameters.Add(outputParameter);

            // 执行存储过程
            command.ExecuteNonQuery();

            // 获取输出参数的值
            string outputValue = outputParameter.Value.ToString();
            Console.WriteLine("Output Parameter: " + outputValue);
        }
    }
}