Linq C中的Nullable Type＃

问题描述

在我的数据库中有一些行为null，我如何使用可空类型或如何在linq中跳过可空行？但我更喜欢使用可空类型而不是跳过行

in my database there is some row which is null and how can i use nullable type or how can i skip nullable row in linq? but i prefer to use nullable type rather than skip rows

推荐答案

用于读取数据的方法，例如。实体框架，SqlClient托管提供者进入DataTable ???

What method is used to read data eg. Entity Framework, SqlClient managed provider into a DataTable???

也许没有DataTable而是使用DataReader

Perhaps no DataTable but instead using a DataReader

if (read.Read())
{
   int colIndex = read.GetOrdinal("MyColumnName");
   maskedTextBox2.Text = read.IsDBNull(colIndex) ? 
                  string.Empty : 
                  read.GetDateTime(colIndex).ToString("MM/dd/yyyy");

}

使用LINQ

var query1 =
    from c in categories
    where c != null
    join p in products on c.ID equals
        p?.CategoryID
    select new { Category = c.Name, Name = p.Name };

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