Crystal Reports problem using a datatable as datasource

Question

I am using the Crystal Reports viewer via C# to update my report.

Within the code I set my datasource as follows:

ReportDoc.SetDataSource(passeddatatable);

crystalReportViewer1.ReportSource=ReportDoc;


The issue is that on my report, I sum an amount field.

When I was using an MS Access database, this field was defined as currency and the datasource was this database.

When I use the datatable, the field is defined as:

dtColumn.DataType = System.Type.GetType("System.Decimal");

Now, this field is not showing a sum on the report as before. I am trying to use a datatable instead of the database.

Thanks