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 在sql表中,由于在c.SetDataSource(d),SPartSalePrice可以为空;例外来请解决它
答案 0 :(得分:6)
使用匿名投影中的null coalescing或conditional运算符来映射null
:
<强>聚结强>
var d = (from s in db.TblSpareParts
select new
{
s.SPartName,
...,
SPartSalePrice = s.SPartSalePrice ?? 0.0,
...
}).ToArray();
条件(对空值不太有用,但对投影其他值很有用)
SPartSalePrice = s.SPartSalePrice == null ? 0.0 : s.SPartSalePrice,
该字段需要提供一个名称(我保留了原始名称SPartSalePrice
),替换type
(0.0
)应与字段类型匹配
答案 1 :(得分:4)
也许您的一个对象值是Null。尝试类似的东西
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?? DBNull.Value,
s.SPartCode?? DBNull.Value,
s.ModelID ?? DBNull.Value,
s.SPartLocation ?? DBNull.Value,
s.SPartActive ?? DBNull.Value,
s.SPartSalePrice ?? DBNull.Value,
}).ToArray();
CrystalReport1 c = new CrystalReport1();
c.SetDataSource(d);
crystalReportViewer1.ReportSource = c;
}
答案 2 :(得分:1)
试试这个:
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, newPartSalePrice = s.SPartSalePrice == null ? 0 : s.SPartSalePrice }).ToArray();
CrystalReport1 c = new CrystalReport1();
c.SetDataSource(d);
crystalReportViewer1.ReportSource = c;
}
}
您应该使用
检查选择中的nulls.SPartSalePrice == null ? 0 : s.SPartSalePrice
如果为null,则为null,则返回0,否则返回该值并将其赋值给新变量
newPartSalePrice = s.SPartSalePrice == null ? 0 : s.SPartSalePrice
答案 3 :(得分:1)
iF数据类型是字符串然后
SPartSalePrice =s.SPartSalePrice == null ? "" : s.SPartSalePrice;
如果数据为空则显示空白,否则显示数据。
如果数据类型是int,那么
PartSalePrice = s.SPartSalePrice == null ? 0 : s.SPartSalePrice
答案 4 :(得分:0)
如果您只有一个可以为空的属性,请检查您的班级:decimal? ,把它放在十进制。对于那些在声明中有问号的属性,只需删除问号并执行即可。