如何編寫用於在classFile中執行存儲過程的C＃代碼

Question

請幫助我 - 如何編寫使用存儲過程獲取數據的代碼？

我得到一個錯誤，因爲不是所有的代碼返回一個值：

public IEnumerable<Employee> GetEmployee() 
{ 
    string sc = ConfigurationManager.ConnectionStrings["ContextDb"].ConnectionString; 

    using (SqlConnection con = new SqlConnection(sc)) 
    { 
     SqlCommand cmd = new SqlCommand("Sp_GetEmployee", con); 
     cmd.CommandType = CommandType.StoredProcedure; 

     con.Open(); 

     SqlDataReader rdr = cmd.ExecuteReader(); 

     while (rdr.Read()) 
     { 
      Employee Emp = new Employee(); 
      Emp.Emp_Id = Convert.ToInt32(rdr["Emp_Id"]); 
      Emp.EmpName = rdr[("EmpName")].ToString(); 
     } 
    } 
} 

Answer 1

那麼，你的代碼幾乎是正確的。您需要添加一些using語句，當然還有，有返回值：

public IEnumerable<Employee> GetEmployee(){ 
    var employees = new List<Employee>(); 
    string sc = ConfigurationManager.ConnectionStrings["ContextDb"].ConnectionString; 

    using (var con = new SqlConnection(sc)) 
    { 
     using (var cmd = new SqlCommand("Sp_GetEmployee", con)) 
     { 
      cmd.CommandType = CommandType.StoredProcedure; 
      con.Open(); 
      using (var rdr = cmd.ExecuteReader()) 
      { 
       while (rdr.Read()) 
       { 
        var Emp = new Employee(); 
        Emp.Emp_Id = Convert.ToInt32(rdr["Emp_Id"]); // what if it's DBNull? 
        Emp.EmpName = rdr[("EmpName")].ToString(); // what if it's DBNull? 
        employees.Add(Emp); 
       } 
      } 
     } 

    } 
    return employees; 
} 

Answer 2

可以yield員工：

while (rdr.Read()) 
{ 
    Employee Emp = new Employee(); 
    Emp.Emp_Id = Convert.ToInt32(rdr["Emp_Id"]); 
    Emp.EmpName = rdr[("EmpName")].ToString(); 

    // Any other properties... 

    yield return Emp; // This is the new line 
}