System.IndexOutOfRangeException上SqlDataReader的值使用C# [英] System.IndexOutOfRangeException on SQLDataReader Value Using C#
问题描述
我有一个返回三个整数一个SqlDataReader。然而,存在这样的情况,当两个整数的将返回空值。
要避开这个问题我写了以下内容:
INT shoppingCartHeadID = 0;
INT BILLID = 0;
INT delID = 0;conn.Open();
读者= comm.ExecuteReader();
如果(reader.Read())
{
shoppingCartHeadID = Convert.ToInt32(读卡器[shoppingCartHeadID]); 如果(!reader.IsDBNull(BILLID))
{
BILLID = Convert.ToInt32(读卡器[BILLID]);
} 如果(!reader.IsDBNull(delID))
{
delID = Convert.ToInt32(读卡器[delID]);
}
}
reader.Close();
不幸的是,我仍然得到错误信息。有什么建议?
PS我也试过这个没有运气
如果(读者[BILLID]!= NULL)
块引用>解决方案我会尝试通过索引而不是列名访问,以防万一你传递一个不存在的列名。
此外,请确保您有一个使用块换你的读者因此即使有你的读者会以这种方式正确关闭和处置,例如异常任何情况下:
...
使用(VAR读卡器= comm.ExecuteReader())
{
如果(reader.Read())
{
shoppingCartHeadID = Convert.ToInt32(阅读[0]); 如果(!reader.IsDBNull(1))
{
BILLID = Convert.ToInt32(阅读器[1]);
} 如果(!reader.IsDBNull(2))
{
delID = Convert.ToInt32(读者[2]);
}
}
}I have a SQLDataReader that returns three integers. However, there are occasions when two of the integers will return null values.
To get round this I wrote the following:
int shoppingCartHeadID = 0; int billID = 0; int delID = 0; conn.Open(); reader = comm.ExecuteReader(); if (reader.Read()) { shoppingCartHeadID = Convert.ToInt32(reader["shoppingCartHeadID"]); if (!reader.IsDBNull(billID)) { billID = Convert.ToInt32(reader["billID"]); } if (!reader.IsDBNull(delID)) { delID = Convert.ToInt32(reader["delID"]); } } reader.Close();
Unfortunately I'm still getting the error message. Any suggestions?
PS I also tried this with no luck
if (reader["billID"] != null)
解决方案I would try to access by index instead of column name, just in case you are passing a not existing column name.
Also, make sure you wrap your reader with a using block so in any case even if there is an exception your reader will be properly closed and disposed, for example in this way:
... using(var reader = comm.ExecuteReader()) { if (reader.Read()) { shoppingCartHeadID = Convert.ToInt32(reader[0]); if (!reader.IsDBNull(1)) { billID = Convert.ToInt32(reader[1]); } if (!reader.IsDBNull(2)) { delID = Convert.ToInt32(reader[2]); } } }
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