The thing is I have this code
var ojv = xmd.ExecuteScalar().ToString();
if (ojv != null)
{
Console.WriteLine(ojv);
var up = CreateQuery();
up.CommandText = "UPDATE characters SET items=@items WHERE accId=@accId AND charId=@charId;";
up.Parameters.AddWithValue("@items", ojv);
up.Parameters.AddWithValue("@accId", acc.AccountId);
up.Parameters.AddWithValue("@charId", charId);
up.ExecuteNonQuery();
var del = CreateQuery();
del.CommandText = "DELETE FROM shop WHERE accId=@accId AND chrId=@chrId;";
del.Parameters.AddWithValue("@accId", acc.AccountId);
del.Parameters.AddWithValue("@chrId", charId);
del.ExecuteNonQuery();
}
But if theres no ovj it return null, I need to avoid that, is there any way so the ExecuteScalar wont return null if no value is found?
ExecuteScalar返回一个数字,如果没有结果集,则返回null,因此您首先需要检查null(在应用ToString()之前),然后解析为整数(或大整数,或小数,无论您需要什么)并检查大于零。
Just check for null before you call ToString().
var result = xmd.ExecuteScalar();
if (result != null)
{
var ojv = result.ToString();
Console.WriteLine(ojv);
var up = CreateQuery();
up.CommandText = "UPDATE characters SET items=@items WHERE accId=@accId AND charId=@charId;";
up.Parameters.AddWithValue("@items", ojv);
up.Parameters.AddWithValue("@accId", acc.AccountId);
up.Parameters.AddWithValue("@charId", charId);
up.ExecuteNonQuery();
var del = CreateQuery();
del.CommandText = "DELETE FROM shop WHERE accId=@accId AND chrId=@chrId;";
del.Parameters.AddWithValue("@accId", acc.AccountId);
del.Parameters.AddWithValue("@chrId", charId);
del.ExecuteNonQuery();
}
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