CODEWITHSUNDEEP
c#datatable
Daniel
Daniel

Reputation: 69

C# datatable computing

I am computing in the large datatable. The table name is templetable.

I am trying to calculate the sum from the 4th column to the last column and save the results to another datatable. But I am getting errors as it says could not find the column "colPnow"

Any ideas?

DataView dv2 = new DataView(SP_dt);

        for (int i = 0; i < LoadIDcount; i++)
        {
            string IDnow = LoadID[i, 0];
            dv2.RowFilter = String.Format("Load_ID = '{0}'", IDnow);
            DataTable temptable = dv2.ToTable();

            for (int j = 0; j < 8760; j++)
            {
                string colPnow = SP_dt.Columns[j*2 + 4].ColumnName.ToString();
                double ColP_sum= (double)temptable.Compute("Sum(colPnow)", String.Format("Load_ID = '{0}'", IDnow));
                string colQnow = SP_dt.Columns[j*2 + 5].ColumnName.ToString();
                double ColQ_sum = (double)temptable.Compute("Sum(colQnow)", String.Format("Load_ID = '{0}'", IDnow));

                Load_dt.Rows[i][j * 2 + 2] = ColP_sum;
                Load_dt.Rows[i][j * 2 + 3] = ColQ_sum;
            }

        }

Upvotes: 2

Views: 218

Answers (1)

Peroxy
Peroxy

Reputation: 646

You are not formatting your expression string correctly in the Compute method. Use another String.Format and it will work. Your Compute expression is currently literally equal to "Sum(colPnow)". You want the actual column name string that is stored in your colPnow variable.

Change this part of your code to this:

string colPnow = SP_dt.Columns[j*2 + 4].ColumnName.ToString();
double ColP_sum= (double)temptable.Compute(String.Format("Sum([{0}])", colPnow),
                                           String.Format("Load_ID = '{0}'", IDnow));

The same should be done for your colQnow variable. I would also suggest you read how String.Format works so that you can grasp the string formatting concept.

Upvotes: 2

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