C# 将错误获取为@Parameter1不是过程的参数

我正在从视频中学习mvc，从表单中获取数据并将其保存到数据库中。当我第一次运行代码时，它给出了一个错误

过程或函数“spaddeemployee”需要参数“@Employee_Name”，但未提供该参数

我采用了一种解决方案，在该解决方案中，我将存储过程初始化为NULL，但现在我收到另一个错误，指出“@Parameter1不是过程的参数”

这是我的存储过程

ALTER PROCEDURE [dbo].[spAddEmployee]
(
    @Employee_Name varchar(max) = NULL,
    @Employee_Age int = NULL,
    @Employee_Salary int = NULL,
    @Employee_City varchar(50) = NULL
)
AS
BEGIN
    INSERT INTO tblEmployee (Employee_Name, Employee_Age, Employee_Salary,  Employee_City)
    VALUES (@Employee_Name, @Employee_Age, @Employee_Salary, @Employee_City)
END

这是我的ADO.NET代码：

public void AddEmployee(Employee employee)
{
    string connectionString = ConfigurationManager.ConnectionStrings["EmployeeContext"].ConnectionString;

    using (SqlConnection con = new SqlConnection(connectionString))
    {
        SqlCommand cmd = new SqlCommand("spAddEmployee", con)
        {
            CommandType = CommandType.StoredProcedure
        };

        SqlParameter paramName = new SqlParameter();
        paramName.ParameterName = "@Employee_Name";
        paramName.Value = employee.Employee_Name;
        cmd.Parameters.Add(paramName);

        SqlParameter paramAge = new SqlParameter();
        paramAge.ParameterName = "@Employee_Age";
        paramAge.Value = employee.Employee_Age;
        cmd.Parameters.Add(paramAge);

        SqlParameter paramSalary = new SqlParameter();
        paramSalary.ParameterName = "@Employee_Salary";
        paramSalary.Value = employee.Employee_Salary;
        cmd.Parameters.Add(paramSalary);

        SqlParameter paramCity = new SqlParameter();
        paramCity.ParameterName = "@Employee_City";
        paramCity.Value = employee.Employee_City;
        cmd.Parameters.Add(paramCity);

        con.Open();
        cmd.ExecuteNonQuery();
    }
}

这是我的控制器代码

[HttpPost]
[ActionName("Create")]
public ActionResult Create_Post(FormCollection formCollection)
{
    Employee employee = new Employee();
    employee.Employee_Name = formCollection["Employee_Name"];
    employee.Employee_Age = Convert.ToInt32(formCollection["Employee_Age"]);
    employee.Employee_Salary = Convert.ToInt32(formCollection["Employee_Salary"]);
    employee.Employee_City = formCollection["Employee_City"];
    
    EmployeeBuissnessLayer employeeBuissnessLayer = new EmployeeBuissnessLayer();
    employeeBuissnessLayer.AddEmployee(employee);
    return RedirectToAction("Index");
}

我在线路上出错了

employeeBuissnessLayer.AddEmployee(employee);

请帮助我，我尝试了很多解决方案，但没有一个有效。

这

    SqlParameter paramName = new SqlParameter();
    paramName.ParameterName = "@Employee_Name";
    paramName.Value = employee.Employee_Name;
    cmd.Parameters.Add(paramName);

应该是

    SqlParameter paramName = new SqlParameter();
    paramName.ParameterName = "@Employee_Name";
    // Always set the datatype
    paramName.SqlDbType = SqlDbType.NVarChar;
    // For strings, always set the length
    paramName.Size = 128; // Max string length
    // Ensure you pass DBNull not C# null
    paramName.Value = employee.Employee_Name ?? System.DBNull.Value;
    cmd.Parameters.Add(paramName);

---

注意：最好的做法是不使用

sp

前缀来命名存储过程。

@DaleK很抱歉，我没有完全理解它。您可以解释我应该在哪里设置System.DBNull.Value。您还需要在

cmd.ExecuteOnQuery（）行停止调试器

并手动检查每个参数的值。@DaleK我过去不太活跃，我对平台也不熟悉，但从现在开始我会这样做。lol我不知道如何通过单击检查符号来接受答案，现在我做到了。谢谢