Read boolean values from DB?
In C#, using SqlDataReader, is there a way to read a boolean value from the DB?
while (reader.Read())
{
destPath = reader["destination_path"].ToString();
destFile = reader["destination_file"].ToString();
createDir = reader["create_directory"].ToString();
deleteExisting = Convert.ToBoolean(reader["delete_existing"]);
skipIFolderDate = reader["skipifolderdate"].ToString();
useTempFile = reader["useTempFile"].ToString();
password = reader["password"].ToString();
}
In the code above, delete_existing is always a 1 or 0 in the DB. I read on MSDN that Convert.ToBoolean() does not accept a 开发者_如何学运维1 or 0 as valid input. It only accepts true or false. Is there an alternative way to convert a DB value to a bool? Or do I need to do this outside of the SqlDataReader?
Also, I can not change the DB values, so please no answers saying, "Change the DB values from 1's and 0's to true's and false's."
Thanks!
If the type of delete_existing
is a sqlserver 'bit' type, you can do :
var i = reader.GetOrdinal("delete_existing"); // Get the field position
deleteExisting = reader.GetBoolean(i);
or (but it will crash if delete_existing
can be DBNull
)
deleteExisting = (bool)reader["delete_existing"];
or better, this onebelow is DBNull
proof and returns false if the column is DBNull
deleteExisting = reader["delete_existing"] as bool? ?? false;
Otherwise if the database type is int
:
deleteExisting = (reader["delete_existing"] as int? == 1) ? true : false;
or if it is a varchar
deleteExisting = (reader["delete_existing"] as string == "1") ? true : false;
Casting works: myVar = (bool)dataReader["myColumn"];
How about this?
deleteExisting = (reader["delete_existing"] as int?) == 1;
Boolean is probably the easist type to convert something to. Here's the 'Y', 'N' version:
deleteExisting = string.Equals(reader["delete_existing"] as string, "Y", StringComparision.OrdinalIgnoreCase);
If you are using CASE in SELECT and want to use GetBoolean then use CAST to change the column to bit before reading.
For eg:
SELECT CAST((CASE WHEN [Condition] THEN 1 ELSE 0 END) as bit) FROM Table_Name
then you can use
reader.GetBoolean(0)
deleteExisting = reader.GetBoolean(reader["delete_existing"]);
精彩评论