no overload for method "ToString" takes 1 arguments
Assuming that TotalPrice is a Decimal column, and that myReader is a DataReader:
TotalPrice.Text = myReader.GetDecimal(myReader.GetOrdinal("TotalPrice")).ToString("N2");The idea here is that myReader's indexer (what you are using when you call myReader["TotalPrice"]) returns an Object. It has to, since it doesn't know at compile time what type the column is. By using .GetDecimal(), you are assuring that you get a Decimal value back, or an error.
The .ToString overload that takes a format string is declared on Decimal, not on Object. Object's .ToString takes no arguments.
The inner call to GetOrdinal returns the field's index given the name- if you are doing this in a loop for multiple data rows, you'd probably want to cache that in a variable.