DataSet不支持System.Nullable<>例外在c# [英] DataSet does not support System.Nullable<> exception in c#
问题描述
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
RST_DBDataContext db = new RST_DBDataContext();
var d = (from s in db.TblSpareParts
select new { s.SPartName, s.SPartCode, s.ModelID, s.SPartLocation, s.SPartActive, s.SPartSalePrice }).ToArray();
CrystalReport1 c = new CrystalReport1();
c.SetDataSource(d);
crystalReportViewer1.ReportSource = c;
}
}
我正在尝试生成水晶报告b $ b在sql表中SPartSalePrice是可空的,因为在c.SetDataSource(d);异常来解决它
i am trying generate crystal report there in sql table SPartSalePrice is nullable due to that at c.SetDataSource(d); exception come please solve it
推荐答案
使用 null coalescing 或条件运算符在您的匿名投影中映射出 null
:
Use the null coalescing or conditional operators in your anonymous projection to map out the null
:
合并:
var d = (from s in db.TblSpareParts
select new
{
s.SPartName,
...,
SPartSalePrice = s.SPartSalePrice ?? 0.0,
...
}).ToArray();
有条件的(对于null而言非常有用,但对投影其他值很有用)
Conditional (Not really useful for nulls, but useful for projecting other values)
SPartSalePrice = s.SPartSalePrice == null ? 0.0 : s.SPartSalePrice,
该字段需要给出一个名称(我保留原来的一个, SPartSalePrice
)和类型
替换( 0.0
)应该匹配字段的类型。
The field needs to be given a name (I've kept the original one, SPartSalePrice
), and the type
of substitution (0.0
) should match the type of the field.
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