我想从数据库中取出第一行第一个单元格的值,它与下面的代码工作得很好.但是当没有找到结果时,它会抛出异常.
如何处理DBNull
System.NullReferenceException: Object reference not set to an instance of an object.
Code:个
public string absentDayNo(DateTime sdate, DateTime edate, string idemp)
{
string result="0";
string myQuery="select COUNT(idemp_atd) absentDayNo from td_atd where ";
myQuery +=" absentdate_atd between '"+sdate+"' and '"+edate+" ";
myQuery +=" and idemp_atd='"+idemp+"' group by idemp_atd ";
SqlCommand cmd = new SqlCommand(myQuery, conn);
conn.Open();
//System.NullReferenceException occurs when their is no data/result
string getValue = cmd.ExecuteScalar().ToString();
if (getValue != null)
{
result = getValue.ToString();
}
conn.Close();
return result;
}