Expression for Calculating a RunningValue column in SSRS Tablix Control

Question

User enters a fixed parameter representing a Credit Limit. Then each row subtracts a different column called [AmountPaid]. So the Balance Available column show what is left and this gets smaller and smaller down the rows to the bottom.

Both column textboxes in Tablix are set to Number type=Currency. Parameter is set to Float. Not many choices of data type for the Parameter input.

I thought this would work in an expression for the Balance Available but it gives me an error. My idea was to do a running Sum and then subtract it from the initial Credit Limit:

=Parameters!CreditLimit.Value - RunningValue(Fields!AmountPaid, Sum, "DataSet1")

The message for the error is: [rsAggregateOfInvalidExpressionDataType] The Value expression for the textrun ‘Textbox23.Paragraphs[0].TextRuns[0]’ uses an aggregate function with an expression that returned a data type not valid for the aggregate function.

If this question could be asked differently I am open to suggestions. Thanks

Answer 1

You need to get the value of AmountPaid so try Fields!AmountPaid.Value`