条件运算符有问题吗?

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问题描述

大家好

请告诉我我哪里错了

这是代码

hi to all

please tell where i am wrong

here is code

obenitiypersonal.reference_date = DateTime.Parse(Txt_reference_date.Text != "" ? Txt_reference_date.Text : (DBNull.Value.ToString ()));

错误:
无法将字符串识别为有效的DateTime.

error:
String was not recognized as a valid DateTime.

推荐答案

obenitiypersonal.reference_date
                    = DateTime.TryParse(Txt_reference_date.Text
                                 , out obenitiypersonal.reference_date) ?
                                obenitiypersonal.reference_date: new DateTime();

DateTime d;
obenitiypersonal.reference_date =
   (DateTime.TryParse(Txt_reference_date.Text, out d))
   ? d
   : DateTime.MinValue;

在这里，我假设obenitiypersonal.reference_date是DateTime结构.
如果obenitiypersonal.reference_date是DateTime?(Nullable<datetime></datetime>)，则可以编写:

Here I assume that obenitiypersonal.reference_date is a DateTime struct.

If obenitiypersonal.reference_date were a DateTime? (Nullable<datetime></datetime>), you could write :

DateTime d;
obenitiypersonal.reference_date =
   (DateTime.TryParse(Txt_reference_date.Text, out d))
   ? d
   : null;

基本上，您不能像您一样从DBNull.Value中获取有效的DateTime值.

Basically you cannot get a valid DateTime value out of DBNull.Value, like you do.

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