How to find columns used in a DataColumn.Expression ?

Question

Looking for a way to find out the columns used in a DataColumn.Expression

it should be possible i hope ?

Answer 1

Hi kumarnyc,

Welcome!

I think you can use Reflector to retrieve the column information:

foreach (var item in table.Columns)
            {
             var test=   item.GetType().GetProperty("Expression").GetValue(item, null);         
            }

Have a nice day.

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Alan Chen[MSFT]
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Answer 2

That's the same as

foreach (var item in table.Columns)
            {
             var test=   item.Expression;
            }

what i am looking for is

given this column def, where f1-f6 are other fields

Columns.Add("formula", typeof(double), " f1 +f2 (f3*f4) + f5 / f6 ");

a method such as DataColumn.GetFieldsUsedInExpression()

which returns f1, f2, f3, f4, f5, f6

Sorry i was not clear earlier

Answer 3

Hi,

The easy way to find the Fields is use Regular Expression here.

http://www.regular-expressions.info/dot.html

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I am fish.

Answer 4

I don't think there is an easy way. You should parse the formula.

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Miha Markic [MVP C#] http://blog.rthand.com

Answer 5

Yea but you have typed those columns, strange question, seems if you are an end user who knows nothing about the program?

Like in a metaphor: "how can I count the toes on my left feet".

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Success
Cor