[英]How to call stored procedure in Entity Framework Core with input and output parameters using mysql
I am using ASP.net Core 2.2 with Entity Framework core 2.2.6 and Pomelo.EntityFrameworkCore.MySql 2.2.0 for connectivity with MySQL, I have a stored procedure which takes 3 input parameters and 1 output parameter. 我可以在 MySQL 工作台中調用它
CALL GetTechniciansByTrade('Automobile', 1, 10, @total);
select @total;
現在我想使用實體框架核心來調用它,我目前使用的代碼是
var outputParameter = new MySqlParameter("@PageCount", MySqlDbType.Int32);
outputParameter.Direction = System.Data.ParameterDirection.Output;
var results = await _context.GetTechnicians.FromSql("Call GetTechniciansByTrade(@MyTrade, @PageIndex, @PageSize, @PageCount OUT)",
new MySqlParameter("@MyTrade", Trade),
new MySqlParameter("@PageIndex", PageIndex),
new MySqlParameter("@PageSize", PageSize),
outputParameter).ToListAsync();
int PageCount = (int)outputParameter.Value;
我目前得到的例外是
CommandType 為 Text 時僅支持 ParameterDirection.Input(參數名稱:@PageCount)
你可以試試下面的東西。
使用 exec 而不是調用
var results = await _context.GetTechnicians.FromSql("EXEC GetTechniciansByTrade(@MyTrade, @PageIndex, @PageSize, @PageCount OUTPUT)"
存儲過程中的 Select PageCount
我從這個 github問題中得到了信息。
我根據這個問題使用@matt-g 建議找到了解決方案。 我不得不為此使用 ADO.net 作為
var technicians = new List<TechnicianModel>();
using (MySqlConnection lconn = new MySqlConnection(_context.Database.GetDbConnection().ConnectionString))
{
lconn.Open();
using (MySqlCommand cmd = new MySqlCommand())
{
cmd.Connection = lconn;
cmd.CommandText = "GetTechniciansByTrade"; // The name of the Stored Proc
cmd.CommandType = CommandType.StoredProcedure; // It is a Stored Proc
cmd.Parameters.AddWithValue("@Trade", Trade);
cmd.Parameters.AddWithValue("@PageIndex", PageIndex);
cmd.Parameters.AddWithValue("@PageSize", PageSize);
cmd.Parameters.AddWithValue("@PageCount", MySqlDbType.Int32);
cmd.Parameters["@PageCount"].Direction = ParameterDirection.Output; // from System.Data
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
technicians.Add(new TechnicianModel()
{
City = reader["City"].ToString(),
ExperienceYears = reader["ExperienceYears"] != null ? Convert.ToInt32(reader["ExperienceYears"]) : 0,
Id = Guid.Parse(reader["Id"].ToString()),
Name = reader["Name"].ToString(),
Qualification = reader["Qualification"].ToString(),
Town = reader["Town"].ToString()
});
}
}
Object obj = cmd.Parameters["@PageCount"].Value;
var lParam = (Int32)obj; // more useful datatype
}
}
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