I have a SQL Server database where sometimes a date column contains NULL
. Now I read that data into an ASP.NET Core page and it stops reading when it encounters the first NULL
column.
That NULL
should be replaced by a space because later this field will get a date. Who can help me?
This is my code:
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System;
using System.Data.SqlClient;
namespace Rectusoft_Tournament_organizer.Pages
{
public class TeamsModel : PageModel
{
public List<TeamInfo1> listTeams = new();
public string? sessionvariable;
//Dit moeten we hierzetten en de variabele instellen
public void OnGet()
{
try
{
String connectionString = "D********************";
using SqlConnection connection = new(connectionString);
connection.Open();
String sql = "select team.naam as teamnaam, land.naam as landnaam, land.vlag, dbo.fnBetalingsdatum(team.id) as datum, division.naam , multiplificator_divisie from team, land, division where team.id_land = land.id and team.id_division = division.Id and team.id_toernooi = '86188502-2c57-4931-addc-9813959bbd97' and team.aktief = 'J' order by multiplificator_divisie desc, CASE WHEN dbo.fnBetalingsdatum(team.id) IS NULL THEN 1 ELSE 0 END, dbo.fnBetalingsdatum(team.id), id_division";
using SqlCommand command = new(sql, connection);
using SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
TeamInfo1 teamInfo1 = new()
{
naam = reader.GetString(0),
land = reader.GetString(1),
vlag = reader.GetString(2),
if (!DBNull.Value.Equals(reader.GetString(3)))
{
//IServerSideBlazorBuilder not null
teamInfo1.betaling = reader.GetDateTime(3).ToString("dd-MMM-yyyy")!= null)
}
else
{
//null
teamInfo1.betaling = reader.GetDateTime(3).ToString("---"),
};
};
listTeams.Add(teamInfo1);
}
}
catch (Exception ex)
{
Console.WriteLine("NOT Connected"); // something like this
Console.WriteLine("Exception: connectie NIET ok " + ex.Message);
}
}
}
public class TeamInfo1
{
public String? naam;
public String? land;
public String? vlag;
public String? betaling;
}
}
If it's returning DBNull
then you cannot read it with GetString
. Instead, use IsDBNull
to check it
betaling = reader.IsDBNull(3) ?
"---" :
reader.GetDateTime(3).ToString("dd-MMM-yyyy"),
Alternatively, use the indexer property on the reader, and safe-cast it to date
betaling = (reader[3] as DateTime)?.ToString("dd-MMM-yyyy") ?? "---",