指定的转换是无效 [英] Specified cast is not valid
问题描述
我几乎与我的项目做,但是最后一个讨厌的bug(我不知道如何解决)是保持我了。
I'm almost done with my project, but one last irritating bug (which I don't know how to fix) is keeping me up.
我想用下面的code至从我的数据库中的 Score_Waarde
值:
I'm trying to get the Score_Waarde
value from my database using the following code :
critid = critid_arr[teller2].ToString();
int scorehulp = 0;
string userid = Session["userid"].ToString();
SqlCommand cmd3 = new SqlCommand("SELECT Score_Waarde FROM Score WHERE Crit_ID = '" + critid + "' AND User_ID = '" + userid + "' ", con);
scorehulp = (int)cmd3.ExecuteScalar();
当我尝试运行此我得到以下错误:指定的转换是无效。
我不明白为什么我得到这个错误,因为 critid
和用户ID
是给正确的值。没有人有一个想法?
When I try to run this I get the following error: Specified cast is not valid.
I don't understand why I'm getting this error because critid
and userid
are giving the correct values. Does anyone have an idea?
grtz,
推荐答案
您的SQL可能是回馈不同的数字类型,如长
或小数
,或,很显然,字符串
。
Your SQL is probably giving back a different numeric type, such as long
or decimal
, or, apparently, string
.
呼叫 Convert.ToInt32
,它不具备<一个href=\"http://blogs.msdn.com/b/ericlippert/archive/2009/03/19/re$p$psentation-and-identity.aspx\">limitations一个拆箱投。
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