请教这样的数据比较为何不等？

[evenhu]

unuseddata.field1 = (field1.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field1.Text.Trim());
unuseddata.field2 = (field2.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field2.Text.Trim());
unuseddata.field3 = (field3.Text.Trim()==String.Empty)?0:Convert.ToInt32(field3.Text.Trim());
unuseddata.field4 = (field4.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field4.Text.Trim());
unuseddata.field5 = (field5.Text.Trim()==String.Empty)?0:Convert.ToInt32(field5.Text.Trim());
unuseddata.field6 = (field6.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field6.Text.Trim());
unuseddata.field7 = (field7.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field7.Text.Trim());
unuseddata.field8 = (field8.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field8.Text.Trim());
unuseddata.field9 = (field9.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field9.Text.Trim());
unuseddata.field10 = (field10.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field10.Text.Trim());
unuseddata.field11 = (field11.Text.Trim()==String.Empty)?0:Convert.ToInt32(field11.Text.Trim());
unuseddata.field12 = (field12.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field12.Text.Trim());
unuseddata.field13 = (field13.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field13.Text.Trim());
unuseddata.field14 = (field14.Text.Trim()==String.Empty)?0:Convert.ToInt32(field14.Text.Trim());
unuseddata.field15 = (field15.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field15.Text.Trim());
unuseddata.field16 = (field16.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field16.Text.Trim());
unuseddata.field17 = (field17.Text.Trim()==String.Empty)?0:Convert.ToInt32(field17.Text.Trim());
unuseddata.field18 = (field18.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field18.Text.Trim());
unuseddata.field19 = (field19.Text.Trim()==String.Empty)?0.0f:Convert.ToSingle(field19.Text.Trim());
unuseddata.field20 = (field20.Text.Trim()==String.Empty)?0:Convert.ToInt32(field20.Text.Trim());

我有如下的数据比较：
Response.Write(unuseddata.field1);
Response.Write(unuseddata.field2+unuseddata.field6+unuseddata.field7+unuseddata.field8);
Response.Write(unuseddata.field9+unuseddata.field12+unuseddata.field15+unuseddata.field18);
Response.Write(unuseddata.field1==(unuseddata.field2+unuseddata.field6+unuseddata.field7+unuseddata.field8));
Response.Write(unuseddata.field1==(unuseddata.field9+unuseddata.field12+unuseddata.field15+unuseddata.field18));

输入测试数据后，打印出来的结果为：
10.18 10.18 10.18 False False
都为10.18,所以后两个打印出来的值都为true才对呀，问题是出在哪里了？？

[evenhu]

还是不行哪

[jjcccc]

Response.Write((unuseddata.field1-(unuseddata.field2+unuseddata.field6+unuseddata.field7+unuseddata.field8))<0.01f);

是这样试的吗？

[阿拉丁]

对float和double类型的数据比较大小严格来说一般不能用相等比较，而是用>或<比较，举例说：，


jjcccc() 说得对，这是基本思路！

[jjcccc]

另最好加上取绝对值一下再比较。

[zag]

精度问题吧。

[evenhu]

jjcccc()

是这样试的，但还是返回false

[jjcccc]

你先用：

float f=unuseddata.field2+unuseddata.field6+unuseddata.field7+unuseddata.field8);
Response.Write(unuseddata.field1.ToString("f5"));
Response.Write(f.ToString("f5"));

看看两个数到底是什么？

[seesea125]

程序换成Convert.ToDouble再比较试试

[evenhu]

两个都是一样的，是10.18000

[evenhu]

如果
Response.Write(unuseddata.field1.ToString("f5") == f.ToString("f5"));这样的话，打印的结果倒是true了，

[evenhu]

看来必须要加ToString("f2") 了，是不是这样子的

[jjcccc]

这样最好

[evenhu]

谢谢 jjcccc() ，我再多测试两次，如果真的OK了，就结

[evenhu]

自己UP一下

[seesea125]

Response.Write((unuseddata.field1).Equals(unuseddata.field9+unuseddata.field12+unuseddata.field15+unuseddata.field18));试试

[jjcccc]

因为unuseddata.field1与unuseddata.field2+unuseddata.field6+unuseddata.field7+unuseddata.field8不相等啊。

因为考虑到float数据的精度问题，上面表达式的左右两边虽然在两位小数位时是一样的，但值不一定相等。

[jjcccc]

对float和double类型的数据比较大小严格来说一般不能用相等比较，而是用>或<比较，举例说：

float f1=0.1293923012;
float f2=0.1293923012001;

比较时根据情况定一个合适比较精度范围：

float delt=0.00000000001;

if ((f2-f1)<delt)
{
//就认为相等
}

[evenhu]

试一下先

[evenhu]

jjcccc() 的方法if ((f2-f1)<delt)
还是返回false

[jjcccc]

精度定义要合适啊，按你的题意，应该：

delt=0.01;