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c#linqdatasetcalculated-columns
Nick
Nick

Reputation: 25799

Typed Dataset Calculated Column using Linq

I have a strongly-typed DataTable returned in a strongly-typed DataSet from a database query. The DataSet is subsequently passed to a ReportViewer to display a chart based on some aspects of the data.

I've added an extra column to the dataset and I'm looping through the table calculating a value for this new column based on one of the columns returned from the database.

The calculated column is a single byte value which is simply the first element of another column which is an array of bytes.

        foreach (ReportData.EventRangeRow row in ReportData.EventRange)
        {
            byte[] analysis = (byte[]) row[ReportData.EventRange.analysisColumn];

            row[ReportData.EventRange.first_analysisColumn] = analysis[0];
        }

Obviously my solution works but is a bit unwieldy, so I was wondering whether anyone could suggest a way of either automatically calculating the column as part of the typed dataset or if not, a linq statement which would achieve the same.

Thanks!

Upvotes: 0

Views: 919

Answers (1)

Martin
Martin

Reputation: 1536

You can do many calculations on the report itself, instead of extending your Dataset.

Let's say you have a datasource "MyDataTable" connected to your report. Then drag a textbox onto the report and right click on it and then choose Expression and you get a nice window for writing expressions with lots of examples

One aggregate function could be... =First(Fields!MyColumn.Value, "MyDataTable")

Check the examples in the window under the category "Common Functions -> Aggregate"

Upvotes: 1

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