为分配一个值，而不是为null [英] assigning a value for instead of null

问题描述

亲爱的，
如果变量即将为null，而没有使用if语句，则赋值的语法是什么?

问题是

Dears,
What is the syntax of assigning a value if the variable is coming null, without using the if statement,

The problem is that

RADentryDate.SelectedDate = DateTime.Parse(row[15].ToString())

有时row[15] is DBNULL

问题是当它为null时，会发生错误.所以我想在值变为空时分配一个默认日期

问候

sometimes the row[15] is DBNULL

The problem is that when it is null, an error occurs. so i want to assign a default date when the value comes null

Regards

推荐答案

如果您要谈论的是从数据库获取可能为null的值，则可以执行以下操作

If you are talking about getting values from a database that might be null you could do something like this

string name = datareader.IsDBNull(0) ? "Unknown Name" : datareader.GetString(0);

否则，您需要详细说明问题.

Otherwise you need to elaborate your question some more.

我认为您不能逃避if，但是可以使用速记语法:

I don''t think you can escape from if, but you can use the shorthand syntax for it:

// maybeNull is the passed parameter - if it''s not null it will be assigned to someVariable, else use valueToAssignIfNull
var someVariable = maybeNull ?? valueToAssignIfNull;

我不是c#专业人士，但我会尝试:

I am no c# pro but I''d try:

RADentryDate.SelectedDate = !DBNull.Value.Equals(row[15]) ? DateTime.Parse(row[15].ToString()) : DateTime.Now;

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