抛出了'System.Data.StrongTypingException'类型的异常C#

Question

if ((booking.BookingsVoucher[i].RedemptionReloc != null)). 

我在这里得到例外.RedemptionReloc在dbase中具有null值

Redemption TimeSttmp 
NULL 
Redemption Reloc 
NULL 
RedeemedCurrencyC 
NULL 
Redeemed Amo_ 
NULL 

尝试使用DBNULL.value.equal(booking.BookingsVoucher [i] .RedemptionReloc).但这也引起了异议.这是异常日志

添加凭证详细信息时出现异常:System.Data.StrongTypingException:表'BookingsVoucher'中列'RedemptionReloc'的值为DBNull.---> System.InvalidCastException:无法将类型为'System.DBNull'的对象强制转换为'System.String'.

Answer 1

将NullValue项更改为Null或Empty,并进行相应的检查.

DataSet1 ds1 = new DataSet1();

        SqlConnection cn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["ContosoUniversity2ConnectionString"].ConnectionString);

        using (cn)
        {
            using (SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM Department", cn))
            {
                adapter.Fill(ds1.Department);
                foreach (DataSet1.DepartmentRow row in ds1.Department.Rows)
                {
                    if (row.Name != null)
                    {
                        Console.WriteLine(row.Name);
                    }

                }
            }
        }