c＃如何在select语句中指定一个not？

Question

I'm using a select method on a dataset to retreive the results that match my condition:

foreach (DataRow dr in dsPone2.Tables["tt-pone"].Select(strWhereCondition))
{
    dsPone.Tables["tt-pone"].ImportRow(dr);
}

How do I change the strWhereCondition from

strWhereCondition += " AND poneid = 0 and aoneid = 0 and tranid = 0";

To where tranid is NOT 0?

Do I use <> or != ?

Answer 1

As is so often the case, consulting the documentation is the way forward. DataTable.Select(string) redirects to DataColumn.Expression to document what's allowed in a filter expression - and the "Operators" list shows <> but not != .

Personally I would try to avoid string-based filtering and use LINQ to DataSet instead, but of course that requires .NET 3.5 or higher.

Answer 2

you have to use the SQL notation <>

in your case tranid <> 0

Answer 3

Use tranid <> 0 .

The syntax for the expressions is described here .

Answer 4

The documentation for the DataColumn.Expression property details the syntax used by the filterExpression parameter of the DataTable.Select method . In the Operators section about a third of the way down the page it says...

Concatenation is allowed using Boolean AND, OR, and NOT operators.

...and also lists a <> comparison operator. So, that should mean you can do either tranid <> 0 or NOT (tranid = 0) .