我在投放时出错，请告诉我为什么 [英] i m getting error of casting please tell me why

问题描述

com = new SqlCommand("SELECT MAX(createddate) FROM Payout_Master WHERE sponcorid='" + code + "'", con);
DateTime date = (DateTime)com.ExecuteScalar();//HERE M GETTING ERROR OF CASTING

if(date!=DateTime.Now.Date)
{

}

[edit]添加了代码块[/edit]

[edit]code block added[/edit]

推荐答案

尝试一下.

Try this.

using( SqlConnection cn =new SqlConnection(ConfigurationManager.ConnectionStrings["Conection Name  here"].ConnectionString))
{
SqlCommand com=new SqlCommand();
com = new SqlCommand("SELECT MAX(createddate) FROM Payout_Master WHERE sponcorid='" + code + "'", con);
con.Open();
var OrderDate = (String)com.ExecuteScalar();
if(!string.IsNullOrEmpty(OrderDate))
{
  DateTime oDate = Convert.ToDateTime(OrderDate);
  // rest of the code.
}

}

如果给定代码根本没有创建日期，则结果将为DBNull(并且不能转换为DateTime).检查结果类型并进行相应转换.

其他说明:
-WHERE sponcorid=''" + code + "''->你知道鲍比表"吗?搜索google，它是第一个热门.
-您将sponcorid与代码进行了比较...但是id并不是代码，反之亦然.

祝你好运！

If there is no created date at all for the given code, the result will be DBNull (and cannot be cast to a DateTime). Check the result type and convert accordingly.

Some other remarks:
- WHERE sponcorid=''" + code + "'' -> You know "Bobby Tables"? Search google, its the first hit.
- you compare sponcorid to code... but an id isn''t a code, and vice versa.

Good luck!

您不能将对象(ExecuteScalar()的返回类型)直接转换为DateTime.

也许您可以尝试以下操作:

Hi,

you cannot cast object (the return type of ExecuteScalar()) to DateTime directly.

Maybe you can try something like the following:

string str = Convert.ToString(com.ExecuteScalar());
DateTime date = DateTime.Parse(str);

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