从数据库读取布尔值？ [英] Read boolean values from DB?

问题描述

在C＃中，使用SqlDataReader，有没有办法从数据库中读取布尔值？

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();
}

在上面的代码中，delete_existing在数据库中始终为1或0。我在MSDN上读到Convert.ToBoolean（）不接受1或0作为有效输入。它仅接受对或错。是否有将DB值转换为布尔值的替代方法？还是我需要在SqlDataReader之外执行此操作？

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 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?

此外，我无法更改数据库值，因此请不要回答：将数据库值从1更改为和0分别为true和false。

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."

谢谢！

推荐答案

如果 delete_existing 的类型是sqlserver位类型，则可以执行以下操作：

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);

或（但如果 delete_existing ，它将崩溃可以是 DBNull ）

or (but it will crash if delete_existing can be DBNull)

deleteExisting = (bool)reader["delete_existing"];

或更好，以下是 DBNull 证明如果列为 DBNull

or better, this onebelow is DBNull proof and returns false if the column is DBNull

deleteExisting = reader["delete_existing"] as bool? ?? false;

否则，如果数据库类型为 int ：

Otherwise if the database type is int :

deleteExisting = (reader["delete_existing"] as int? == 1) ? true : false;

或者如果它是 varchar

deleteExisting = (reader["delete_existing"] as string == "1") ? true : false;

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