OdbcDataReader存在奇怪的问题。GetBoolean()引发的强制转换对于bool列无效

val1 = reader.GetInt32(0);
val2 = reader.GetBoolean(4);
val3 = reader.GetBoolean(8);

然而,这并不意味着:

val3 = reader.GetBoolean(8);
val1 = reader.GetInt32(0); // causes invalid cast exception
val2 = reader.GetBoolean(4);

显然,列顺序与此有关。

我不认为将System.String传递给GetBoolean()会对您起作用-您可以从异常中看到,您得到的是一个InvalidCastException,这意味着它在内部某处尝试执行以下操作:

string s = "true";
bool b = (bool)s;

这显然行不通。

我们使用此模式从OdbcDataReader中获取布尔数据:

data.Gender = reader["Gender"] == DBNull.Value ? 
    false : Convert.ToBoolean(reader["Gender"]);

我遇到了同样的问题,实际上是因为我调用的SP中有无效的强制转换。。。

declare @colA INT -- should have been a float!!!
set @colA = select someValue from someTable

select @someVar, someColumn
from someOtherTable

 //the line below works, even though it should have the SQL datatype is FLOAT
 _someVar = reader[2] != DBNull.Value ? reader.GetDouble[2] : 0;
  //the following line blows up w/invalid cast exception, even though it is correct
 _someColumn = reader[3] != DBNull.Value ? reader.GetBoolean[3] : false;