无法将列'EffectiveDate'设置为null。请改用DBNull。

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我收到错误无法将列'EffectiveDate'设置为null。请改用DBNull。 我的代码是

dt.Columns.Add（ EffectiveDate， typeof （DateTime））; DateTime？ effectivedate = null ; if （lastRow [ Effective_x0020_Date]！= DBNull.Value） { effectivedate = Convert.ToDateTime（lastRow [ Effective_x0020_Date]）; } DataRow dr = dt.NewRow（）; dr [ EffectiveDate] = effectivedate; dt.Rows.Add（dr）;

i跟随很多东西 codeverge/asp.presentation-controls/how- to-return-dbnull.value-inst / 487162 [ ^ ] 但同样的错误我正在获取

解决方案

只是因为lastRow [Effective_x0020_Date]是DBNull吗？那么你将在effectivedate中得到初始值（null）; 在分配数据行值时，尝试使用空合并运算符 dr [ EffectiveDate] = effectivedate ?? DBNull.Value;

hi, i am getting error Cannot set Column 'EffectiveDate' to be null. Please use DBNull instead. my code is

dt.Columns.Add("EffectiveDate", typeof(DateTime)); DateTime? effectivedate=null; if (lastRow["Effective_x0020_Date"] != DBNull.Value) { effectivedate = Convert.ToDateTime(lastRow["Effective_x0020_Date"]); } DataRow dr = dt.NewRow(); dr["EffectiveDate"] = effectivedate; dt.Rows.Add(dr);

i followed many things codeverge/asp.presentation-controls/how-to-return-dbnull.value-inst/487162[^] but same error i am getting

解决方案

COuld it simply be that lastRow["Effective_x0020_Date"] is DBNull? Then you would have the initial value (null) in effectivedate; When assigning the data row value, try using null coalescing operator

dr["EffectiveDate"] = effectivedate ?? DBNull.Value;